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A pelvic nerve array is custom designed for implantation onto the pelvic nerve of male rats. This device is used for long-term (recovery) experiments. The device can electrically stimulate the pelvic nerve as well as record electrically evoked or spontaneous neural activity. Previously, we have successfully implanted rats for 2 months with no reports of biological adverse complications or damage sustained to the array. The surgical procedure is performed under anesthesia and should incorporate all local requirements for standards of animal experimentation, including methods of anesthesia, surgical environment, and post-operative monitoring and care.

To investigate the feasibility of erectile function restoration by the genitofemoral nerve to pelvic nerve transfer in rats.Thirty-six male rats were included in this study. Rats in the nerve transfer group (n = 12) were subjected to pelvic nerve, sacral roots, and L6 roots transection and then bilateral genitofemoral nerve to pelvic nerve transfer, rats in the nerve resection group (n = 12) were subjected to pelvic nerve, sacral roots, and L6 roots transection without nerve transfer, and rats in the control group (n = 12) served as controls. After reinnervation, intracavernous pressure (ICP) assessment was performed. Fluoro-Gold was injected into the corpus cavernosum. Immediately before euthanasia, transferred nerves were stimulated to test penile intracavernous pressure. The L6, S1, and L1-2 spinal cord segments were used for retrogradely labeled neurons. Regenerative nerve morphologic examination assessment was performed.Genitofemoral nerve stimulation induced an increase in ICP in the nerve transfer group. The mean ICP in this group was (33.8 ± 9.4 mm Hg), which is higher than the mean value in the nerve resection group (3.9 ± 1.0 mm Hg) but lower than that in the control group (69.8 ± 12.2 mm Hg; P.05). The formation of new neural pathways was confirmed by the appearance of Fluoro-Gold labeled neurons in the L-1 and L-2 spinal cord segments in the nerve transfer group. Regenerative nerve morphologic examination showed good axonal regeneration after genitofemoral nerve transfer.Nerve regeneration can be obtained by genitofemoral nerve to pelvic nerve transfer, and erectile function can be restored.

A pelvic nerve array is custom designed for implantation onto the pelvic nerve of male rats. This device is used for long-term (recovery) experiments. The device can electrically stimulate the pelvic nerve as well as record electrically evoked or spontaneous neural activity. Previously, we have successfully implanted rats for 2 months with no reports of biological adverse complications or damage sustained to the array. The surgical procedure is performed under anesthesia and should incorporate all local requirements for standards of animal experimentation, including methods of anesthesia, surgical environment, and post-operative monitoring and care.

BackgroundTreatment of female pelvic malignancies often causes pelvic nerve damage. Magnetic resonance (MR) neurography mapping the female pelvic innervation could aid in treatment planning.PurposeTo depict female autonomic and somatic pelvic innervation using a modified 3D NerveVIEW sequence.Material and MethodsProspective study in 20 female volunteers (n = 6 normal, n = 14 cervical pathology) who underwent a modified 3D short TI inversion recovery (STIR) turbo spin-echo (TSE) scan with a motion-sensitive driven equilibrium (MSDE) preparation radiofrequency pulse and flow compensation. Modifications included offset independent trapezoid (OIT) pulses for inversion and MSDE refocusing. Maximum intensity projections (MIP) were evaluated by two observers (Observer 1, Observer 2); image quality was scored as 2 = high, 1 = medium, or 0 = low with the sciatic nerve serving as a reference. Conspicuity of autonomic superior (SHP) and bilateral inferior hypogastric plexuses (IHP), hypogastric nerves, and somatic pelvic nerves (sciatic, pudendal) was scored as 2 = well-defined, 1 = poorly defined, or 0 = not seen, and inter-observer agreement was determined.ResultsImages were of medium to high quality according to both observers agreeing in 15/20 (75%) of individuals. SHP and bilateral hypogastric nerves were seen in 30/60 (50%) of cases by both observers. Bilateral IHP was seen in 85% (34/40) by Observer 1 and in 75% (30/40) by Observer 2. Sciatic nerves were well identified in all cases, while pudendal nerves were seen bilaterally by Observer 1 in 65% (26/40) and by Observer 2 in 72.5% (29/40). Agreement between observers for scoring nerve conspicuity was in the range of 60%–100%.ConclusionModified 3D NerveVIEW renders high-quality images of the female autonomic and pudendal nerves.

Background Mechanosensitive afferents innervating the bladder increase their firing rate as the bladder fills and pressure rises. However, the relationship between afferent firing rates and intravesical pressure is not a simple linear one. Firing rate responses to pressure can differ depending on prior activity, demonstrating hysteresis in the system. Though this hysteresis has been commented on in published literature, it has not been quantified. Results Sixty-six bladder afferents recorded from sacral dorsal root ganglia in five alpha-chloralose anesthetized felines were identified based on their characteristic responses to pressure (correlation coefficient ≥ 0.2) during saline infusion (2 ml/min). For saline infusion trials, we calculated a maximum hysteresis ratio between the firing rate difference at each pressure and the overall firing rate range (or Hmax) of 0.86 ± 0.09 (mean ± standard deviation) and mean hysteresis ratio (or Hmean) of 0.52 ± 0.13 (n = 46 afferents). For isovolumetric trials in two experiments (n = 33 afferents) Hmax was 0.72 ± 0.14 and Hmean was 0.40 ± 0.14. Conclusions A comprehensive state model that integrates these hysteresis parameters to determine the bladder state may improve upon existing neuroprostheses for bladder control.

The afferent nervous system plays an important role in the regulation of lower urinary tract (LUT) function. Multiple methods to study the afferent nervous system in the LUT have been described. This overview focuses on extracellular afferent nerve recordings of the pelvic and hypogastric nerves in cat, rat, mouse, and guinea pig from in vivo and in vitro models and considers how such recordings may lend to the understanding of interspecies differences. Neurourol. Urodynam 30:647-652, 2011.

Information about colorectal distension (i.e., colorectal dilation by increased intraluminal pressure) is primarily encoded by stretch-sensitive colorectal afferents in the pelvic nerve (PN). Despite anatomic differences between rectum and distal colon, little is known about the functional roles of colonic vs. rectal afferents in the PN pathway or the quantitative nature of mechanosensory encoding. We utilized an in vitro mouse colorectum-PN preparation to investigate pressure-encoding characteristics of colorectal afferents. The colorectum with PN attached was dissected, opened longitudinally, and pinned flat in a Sylgard-lined chamber. Action potentials of afferent fibers evoked by circumferential stretch (servo-controlled force actuator) were recorded from the PN. Stretch-sensitive fibers were categorized into the following four groups: colonic muscular, colonic muscular/mucosal, rectal muscular, and rectal muscular/mucosal. Seventy-nine stretch-sensitive PN afferents evenly distributed into the above four groups were studied. Rectal muscular afferents had significantly greater stretch-responses than the other three groups. Virtually all rectal afferents (98%) had low thresholds for response and encoded stimulus intensity into the noxious range without obvious saturation. Most colonic afferents (72%) also had low thresholds (18 mmHg) for response. These high-threshold colonic afferents were sensitized to stretch by inflammatory soup; response threshold was significantly reduced (from 23 to 12 mmHg), and response magnitude significantly increased. These results suggest that the encoding of mechanosensory information differs between colonic and rectal stretch-sensitive PN afferents. Rectal afferents have a wide response range to stretch, whereas high-threshold colonic afferents likely contribute to visceral nociception.

Recurrent inhibition of the bladder C fibre reflex was studied in adult female cats anaesthetized with α-chloralose. Test reflexes were evoked by electrical stimulation of bladder Aδ and C afferents in the right pelvic nerve and were recorded from the proximal end of a small ipsilateral pelvic nerve branch, transected close to the bladder. Such test reflexes were consistently depressed by repetitive electrical stimulation of the contralateral bladder pelvic nerve (20 Hz, 20 s) at intensities sufficient to recruit axons of bladder preganglionic neurones. The inhibition could be evoked after transection of the left dorsal roots S1–S4 and the sympathetic supply to the bladder but was abolished by transection of the pelvic nerve central to the site of stimulation. Hence, it most likely involved central recurrent collaterals of antidromically activated bladder preganglionic neurones. The reflex suppression was quite considerable – maximal C fibre reflexes were reduced to a group mean of 25% (± 9% confidence interval) of their control size. The effect had a slow onset, requiring a few seconds of conditioning stimulation to be revealed, and was very long lasting (minutes). Naloxone (0.01–0.5 mg kg−1i.v.) abolished the recurrent inhibition of both the C fibre and Aδ bladder reflexes, while inhibition from afferents in the dorsal clitoris nerve remained unchanged. It is concluded that the segmental bladder C fibre reflex and the spino-ponto-spinal Aδ micturition reflex are both targets of recurrent inhibition from bladder parasympathetic preganglionic neurones and that the effect involves an enkephalinergic mechanism.

Using the thiocholine method and histological techniques the intermesenteric plexus of the pigeon was studied. The intermesenteric plexus of this species is a plexo-ganglionic structure with several (five to seven) ganglia and nerve fibres. The ganglia have an oval-, spindle- or star-like shape. Single nerve cells along the nerve fibres were observed. The intermesenteric plexus of the pigeon is situated on the ventrolateral surface of the aorta, between the cranial mesenteric artery and caudal mesenteric artery. The connections between the intermesenteric and other vegetative plexuses (coeliac plexus, mesenteric inferior plexus) and the pelvic nerve were observed.

We studied evoked potentials (EP) and responses of single neurons in fields 24 and 25 of the cingulate gyrus of the cat brain cortex. The responses were elicited by stimulations of a parasympathetic, a sympathetic, and a somatic nerve (the pelvic, splanchnic, and sciatic nerves). The configuration and amplitude/temporal characteristics of both EP and neuronal responses showed that the organization of the visceral and somatic afferent inputs to the cortical fields under study is to a great extent similar. Localization of the foci of maximum activity for EP within field 24 and their overlapping, the higher responsiveness of the neurons of this field to afferent volleys as compared with that in field 25, the dominance of short-latency neuronal responses in field 24, and the presence of polysensory neurons with modally specific opposite responses in this field allow us to conclude that field 24 (compared with field 25) plays a more significant role in the perception and analysis of viscerosomatic afferent information. Taking into account earlier published data that the zones of concentration of the efferent neurons (forming a descending limbico-sympathetic discharge in the L2-L3 white connective branches and a limbico-parasympathetic discharge in the pelvic nerve) are localized within field 25 and overlap each other, we discuss the functional roles of fields 24 and 25 of the cingulate gyrus in viscerosensory and visceromotor control.

The striated muscle forms an outer sleeve around the urethra and occupies about 80% of the wall. In humans more than 60% of the muscle consists of slow, fatigue resistant type I fibres whereas in male greyhounds only about 6% are type I. Most of the remainder (70% of fibres) are type IIa which are classified as fast but can contract for several hours with little decline in amplitude. Stimulation of pudendal but not pelvic nerves produces contraction of the striated muscle and a rapid increase in urethral pressure. Pelvic nerve branches enter the striated muscle sleeve but pass through it to supply the inner layer of smooth muscle. The striated muscles are well suited to maintain contraction necessary for continence.

In the rat the pelvic nerve consists of a viscerocutaneous (sensory) branch which receives information from pelvic viscera and the midline perineal region, and a somatomotor (muscular) branch which innervates the ilio- and pubococcygeous muscles. To investigate the contribution of these branches to the parturition process, the length of gestation and course of delivery were closely monitored in 43 pregnant, Wistar-strain rats randomly assigned to five groups: untreated control animals, animals in which the somatomotor branch of the pelvic nerve was bilaterally sectioned on Day 14 of gestation, animals in which the viscerocutaneous branch of the pelvic nerve was bilaterally sectioned on Day 14 of gestation, animals treated similarly to the previous group but with young delivered by C-section at term, and sham-operated controls. Sectioning the viscerocutaneous branch seriously disrupted parturition and resulted in major dystocia and a high percentage of stillbirths in all females. In contrast, sectioning the somatomotor branch had no apparent effect on parturition and no significant differences were found between females of this group and sham or control dams on any of the measures recorded. It is concluded that the viscerocutaneous branch of the pelvic nerve is vital for the normal course of parturition in the rat but that the somatomotor branch plays little role, if any.

Background: We examined the mechanism of urinary bladder motility return after bladder areflexia induced by interruption of the sacral parasympathetic outflow to the urinary bladder following damage to the sacral cord or pelvic nerves in the rat. Methods: The L6 and SI nerve bundles were resected near the vertebrae, and bilateral pelvic nerve resections (PNR) performed. Spinal cord injury (SCI) was performed by means of a legion generator at the T12 vertebra. Thirty days after PNR and SCI, cystometrograms were recorded under anesthesia. Results: In all rats subjected to PNR or SCI, overflow incontinence continued, yet some rats subjected to SCI recovered within 2 weeks after the operation. Cystometrograms showed that repetitive bladder contractions appeared in rats subjected to SCI irrespective of hypogastric nerve (HCN) innervation, while bladder contractions did not appear in rats subjected to PNR. Electrical stimulation of the HGN induced higher bladder pressure elevation in rats who underwent PNR than in rats subjected to SCI. Conclusions: These results suggest that the generation of repetitive bladder contractions induced by bladder distention after bladder areflexia requires the presence of intact pelvic nerves that transmit sacral cord-originating excitatory information to the bladder. However, the HGN system and functioning pelvic nerve ganglia are not involved in this process. Also, the connection from the preganglionic HGN to the postganglionic parasympathetic nerves in the pelvic plexus did not form after PNR.

Su, X., J. N. Sengupta, and G. F. Gebhart. Effects of opioids on mechanosensitive pelvic nerve afferent fibers innervating the urinary bladder of the rat. J. Neurophysiol. 77: 1566–1580, 1997. A total of 443 pelvic nerve afferent fibers in the L6 dorsal root of the rat were identified by electrical stimulation of the pelvic nerve; 319 (72%) were myelinated Aδ fibers with a mean conduction velocity (CV) of 11.8 m/s and 124 (28%) were unmyelinated C fibers with mean CV of 1.9 m/s. Two hundred fifty-two fibers (57%) responded to noxious urinary bladder distension (UBD; 80 mmHg); 108 were C fibers (mean CV: 1.9 m/s) and 144 were Aδ fibers (mean CV: 8.2 m/s). Forty-nine UBD-sensitive fibers were further characterized; all gave monotonic increases in firing to increasing distending pressures. Thirty-six fibers (73%) had a low-threshold (LT) for response (mean: 6 mmHg) and 13 fibers (27%) had high-thresholds (HT) for response (mean: 32 mmHg). Responses of 15 fibers to graded UBD (11 LT and 4 HT) were tested before and after instillation of 0.5 ml of 30% xylenes ( n = 11) or 5% mustard oil ( n = 4) into the bladder. The mean resting activity of 13 fibers significantly increased, and 7 fibers exhibited sensitization of responses to graded UBD 30 min after xylenes or mustard oil instillation. All 4 HT fibers were sensitized; 3 of the 11 LT fibers were sensitized (i.e., gave increased responses to UBD). The effects of opioid receptor agonists were tested on responses to noxious UBD (80 mmHg). Cumulative intraaterial doses of μ-opioid receptor agonists (morphine, 8 mg/kg, and fentanyl, 300 μg/kg) and of δ-opioid receptor agonists (DPDPE, 300 μg/kg, and SNC-80, 300 μg/kg) did not affect responses to noxious UBD. In contrast, cumulative 16 mg/kg intraarterial doses of the κ-opioid receptor agonists U50,488H, U69,593 and U62,066 dose-dependently attenuated responses to noxious UBD. There were no differences in the dose-response relationships of these drugs on afferent fibers from untreated and xylenes- or mustard oil-treated urinary bladder. These results reveal that there is a greater proportion of UBD-sensitive fibers in the L6 dorsal root (57%) than in the S1 dorsal root of the rat (38%; a previous study). The attenuation of responses to UBD by κ, but not μ or δ opioid receptor agonists suggests a potential use for peripherally acting κ opioid receptor agonists in the control of urinary bladder pain.

1. Mapping experiments were performed in the region of the ventral posterolateral nucleus of the lateral thalamus in pentobarbitone-anesthetized cats with the aim to locate foci with input from the electrically stimulated pelvic nerve. The locations of the recording sites were verified in Nissl-stained histological sections with reference to electrolytic lesions. 2. Of the 68 visceroceptive thalamic neurons identified, 63% were located in the periphery of the ventral posterolateral nucleus (VPLp) and 34% in the dorsal, lateral, and medial aspects of the posterior complex (POd, POl, and POm, respectively) directly adjacent to VPLp. The region surrounding the middle and caudal part of the ventral posterolateral nucleus (VPL) received a much denser input from the pelvic nerve than that around the rostral pole of VPL. 3. The response latencies of the thalamic neurons to pelvic nerve stimulation ranged from 10 to 65 ms (median: 16 ms; interquartile distance: 12–20 ms) indicating a transmission of information from the pelvic space via small and large diameter myelinated fibers. 4. Seventy-nine percent of the visceroceptive neurons tested (n = 58), in addition, had low threshold somatic receptive fields that were located in 67% of the cases in regions of the lower back, the thigh, the tail and/or the heel and in 26% of the cases on the hindfoot. None of the 40 visceroceptive neurons tested with noxious mechanical stimulation of the skin responded to this kind of stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)

1. Single-unit activity was recorded from S1 sacral dorsal root afferent fibers in the anesthetized rat. A total of 364 afferent fibers were identified by electrical stimulation of the pelvic nerve and subsequently tested for response to colorectal distension (CRD) and urinary bladder distension (UBD). Sixty-seven percent (n = 244) of the fibers were unmyelinated C-fibers and 33% (n = 120) were thinly myelinated A delta-fibers. 2. In three initial experiments, 35 fibers were identified by pelvic nerve stimulation and tested for response only to CRD; none of these fibers responded to CRD. In 20 subsequent experiments, 329 pelvic nerve afferent fibers were tested for response to CRD and UBD. Thirty-four percent (n = 112) of the 329 fibers were unresponsive to noxious CRD (80 mmHg) or to UBD (slow filling < or = 100 mmHg), 44% (n = 146) responded to UBD, 16% (n = 53) responded to CRD, and 6% (n = 18) responded to mechanical stimulation of the anal mucosa. 3. Of the total of 53 pelvic nerve afferent fibers that responded to CRD, 43 (81%) were C-fibers (mean: 1.5 m/s) and 10 (19%) were A delta-fibers (mean: 4.7 m/s). Fifteen of the CRD-sensitive fibers had no resting activity, whereas 38 fibers exhibited some resting activity (mean: 2.6 imp/s). 4. Reproducibility of responses to repeated CRD (80 mmHg, 30s, 10 trials at 4-min intervals) was tested in 17 fibers. In 16, responses to repeated distension were reproducible without evidence of facilitation or inhibition of subsequent responses. One fiber gave greater responses during the 9th and 10th trials. 5. Responses to graded CRD were studied in 44 fibers. All fibers exhibited monotonic, increasing stimulus-response functions < or = 80 mmHg of distension. Thresholds for response of the 44 fibers were determined after extrapolation of the least-squares linear-regression line to the ordinate and varied between 0 and 40 mmHg. Two populations of pelvic nerve afferent fibers in the colon were apparent: low threshold (LT) afferent fibers had a mean threshold of 2.9 mmHg (range: 0-10 mmHg; n = 34) and high threshold (HT) afferent fibers had a mean threshold of 32.6 mmHg (range: 28.0–40.0 mmHg; n = 10). 6. Chemosensitivity to bradykinin (BK) was tested in nine LT fibers. Seven fibers responded to BK (0.1 to 100 micrograms/kg ia) and two fibers did not respond up to 100 micrograms/kg of BK. Responses to BK tested in three fibers were dose dependent.(ABSTRACT TRUNCATED AT 400 WORDS)

The role of the pelvic nerve branches in the mediation of copulatory behavior was investigated. The somatomotor or the viscerocutaneous branch of the pelvic nerve was bilaterlly sectioned in sexually experienced male rats. Somatomotor branch surgery had no detectable effect. Viscerocutaneous branch transection altered copulatory parameters that reflect impairments in penile erection and seminal plug emission. The altered behavioral parameters approached or reached presurgical and sham values 21 days after transection, indicating that the damage to erectile and ejaculatory function was transient. It is suggested that animals with viscerocutaneous branch transection recover copulatory efficiency through a compensatory plastic mechanism, possibly involving the hypogastric nerve.

BACKGROUND: Defects of the pelvic nerve innervation of levator ani muscle are associated with poor postoperative anorectal function in patients with anorectal malformation (ARM). We have previously shown deficient development of motoneurons innervating the levator ani muscle in rats with ARM. In this study we investigate whether there is a deficiency in the development of sensory neurons that innervate the levator ani muscle in rats with ARM. METHODS: ARM was induced by ethylenethiourea (ETU) in fetal rats. Retrograde tracer fluorogold (FG) was injected into the levator ani muscle. Serial transverse sections encompassing the entire length of the lumbosacral spinal cord were examined. The number of FG-labeled sensory neurons was scored and compared between fetuses with ARM and normal fetuses. RESULTS: The number of FG-labeled sensory neurons innervating the levator ani muscle in normal control fetuses, ETU-fed fetuses with no malformation, low type of imperforate anus, high type of imperforate anus, and high type of imperforate anus combined with neural tube defects were determined to be (mean ± SEM) 11,804 ± 2362, 10,429 ± 1708, 2886 ± 705, 1026 ± 425, and 964 ± 445, respectively. FG-labeled sensory neurons in fetuses with imperforate anus with or without neural tube defects were significantly fewer than in control and ETU-fed fetuses without malformation (p < 0.05). CONCLUSIONS: Defective sensory neurons innervating the levator ani muscle is a primary anomaly that coexists with the alimentary tract anomaly in ARM during fetal development. Nerve innervation deficiency of the pelvic muscles contributes to the poor postoperative anorectal functions in ARM patients. Birth Defects Research (Part A), 2009. © 2009 Wiley-Liss, Inc.

Background The exact mechanisms of action of intravesical electrical stimulation (IVES) are not yet fully understood. Objective To gain more insight into the underlying mechanism(s) of the direct detrusor response during IVES by transsecting the dorsal roots and the pelvic nerve consecutively at different levels and to determine whether the efficiency of IVES to induce contraction could be enhanced by simultaneous bladder filling and IVES and by changing the bladder-filling grade. Design, Setting, and Participants Eighteen Sprague-Dawley rats underwent IVES (square-wave pulses at 10 Hz, 20-ms pulse duration). Measurements In seven rats, IVES-induced bladder-pressure development was studied after the bladder nerves were consecutively sectioned bilaterally at four different levels: no lesion, L6 dorsal roots, L6 ventral roots, pelvic nerve, and major pelvic ganglion with surrounding nerves. Bladder-pressure development induced by IVES with simultaneous bladder filling, by bladder filling alone, and by IVES alone was recorded in seven other rats, and bladder-pressure development induced by IVES with different grades of bladder filling was recorded in four rats. Results and Limitations Contraction during IVES was significantly weaker after consecutive section of more nerves (all p < 0.001), but a small contraction (19 ± 17% of baseline) could be elicited even after total decentralization. In the neurologically intact rats, separate stimulation and bladder filling gave contraction strengths similar to those of simultaneous bladder filling and stimulation, but the latter gave contraction after a significantly shorter stimulation time (both p < 0.015). Conclusions IVES-induced contraction is, for the major part, a nerve-mediated process. However, a small bladder-pressure rise was induced by direct bladder-wall stimulation after all nerves were cut. Simultaneous electrical stimulation and bladder filling needed much shorter stimulation times than bladder filling alone or stimulation alone. If confirmed in humans, this could shorten IVES sessions substantially without altering the contractile results and could indicate that summation of afferent potentials from different triggers is possible.

Electrical stimulation (20–35 Hz, 2–5 V, 1.5 h) of the pelvic nerve in urethane-anesthetized rats increased the expression of c-fos protein-immunoreactivity primarily in neurons in the L6–S1 segements of the spinal cord. The neurons were localized to areas receiving afferent input from the pelvic viscera including the superficial dorsal horn, the dorsal commissure, and lateral laminae V–VII in the region of the sacral parasympathetic nucleus. These experiments indicate that (1) electrical stimulation of abdominal nerves following surgical exposure is a useful method for tracing visceral afferent pathways and (2) afferent information from the pelvic viscera is received by neurons in specific areas of the dorsal horn.

In 69 dogs with divided hypogastric nerves anesthetized with ketamine and chloralose the outflows of the pelvic vesical branch (PV) and pudendal urethral branch (PU) were recorded, and effects of amygdaloid and olfactory tubercle stimulation on them were studied. Stimulation (2-100 Hz, 3 ms, 0.2 mA) was applied to the amygdaloid body and olfactory tubercle. When the bladder contraction was induced by amygdaloid stimulation, the increased PV and decreased PU appeared after latencies of about 115 and 110 ms, respectively. When the bladder relaxation was, oppositely, elicited by stimulation, the decreased PV and enhanced PU occurred after latencies of 110 and 90 ms, respectively. The PV excitation was elicited by medial parts of the intermediate principal nucleus, medial parts of the medial principal nucleus, a part of cortical nucleus and of pericortical nucleus. Inhibition of PV was induced by lateral parts of the medial principal nucleus, medial nucleus, central nucleus and a part of the pericortical nucleus. Olfactory tubercle stimulation elicited PV excitation and PU inhibition with latencies of about 100 ms. The vesicopressor response from the tubercle was not abolished by section of the medial preoptic area, medial hypothalamus and periaqueductal gray, but was abolished by added section of the lateral preoptic area, lateral hypothalamus and lateral mesencephalic tegmentum. At the rostral pontine level, the response was abolished by partial section of the lateral part of the pontine reticular formation ipsilateral to the stimulation.

骨盤神経を介して, 骨盤内臓を支配する交感神経と陰部神経, 坐骨神経, 脛骨神経, 総腓骨神経を介して四肢体幹を支配する交感神経の中に起始細胞を同じくする神経が在るやいなやを標識部位の異なる二種類の螢光色素を用い検討した。その結果, 両神経に対する主要分節であるL7-S2 (3) 幹神経節の間で, 二重標識細胞の存在が認められた。その割合は骨盤内臓を支配する節後細胞の平均約0.73%であった。このような二重標識細胞の存在は, 鍼灸作用の構造を考察する上で, 自律神経が末梢の神経節でも遠隔部や四肢体幹の統合, 拡散, 収束等の場になり得る可能性を示唆するものである。

Cerebral evoked potentials (EPs) were recorded in 25 neurologically normal subjects aged 22–73 years (mean 44.0) after stimulation of the posterior urethra (PU) and the pudendal nerve. After maximal PU stimulation 2 different configurations of the potential were found. In 12 cases a simple bi-triphasic wave form was recorded while in 12 cases there was a bifid form of the first negative wave. In 1 case identical EPs were recorded after PU and pudendal nerve stimulation. It was concluded that (1) PU stimulation excites fibres in the pudendal nerve at higher stimulation strength, resulting in a bifid wave form of the cerebral evoked potential in some individuals, (2) the most prominent negative peak, N1, with a latency of 102.1 ± 13.2 msec, is the most reproducible part of the PU-evoked potential, (3) the N1 is probably transmitted through Aδ fibres localized in the pelvic nerves, (4) there are differences between individuals concerning pudendal and pelvic nerve involvement in afferent innervation of the urethra.

Single medullary reticular formation (MRF) neurons receive multiple somatovisceral convergent inputs originating from many different spinal and cranial nerves, including the pelvic nerve (PN), dorsal nerve of the penis (DNP), and the abdominal branches of the vagus. In a previous study, the input to MRF from the male genitalia was shown to be eliminated with chronic 30-day dorsal hemisection at the T8 spinal level. In this study, the effect of a smaller chronic lesion [dorsal column lesion (DCx)] on MRF neuronal responses was examined. Responses to bilateral electrical stimulation of the DNP remained. MRF neuronal responses to non-noxious (touch/stroke) levels of penile stimulation, however, were eliminated; only responses to noxious pinch remained. No differences were found for the number of neurons responding to noxious distention of the colon between the DCx and control groups. Although no differences were found across these groups for the percent MRF responses to vagal stimulation, the mean response latency for the DCx group was twice the sham-DCx/intact control group. Taken together, these results indicate that the MRF receives at least some of its input from the male genitalia via pathways located within the dorsal columns at the mid-thoracic spinal level.

Reflex plasticity between pelvic afferent and pudendal efferent nerve fibers was examined in anesthetized rats. Brief high-frequency electric stimulation (300 pulses at 100 Hz) of the pelvic nerve afferent fiber produced a long-lasting potentiation of the pelvic-to-pudendal reflex (PPR). This tetanization-induced potentiation was abolished by a selective N-methyl-d-aspartate (NMDA) receptor antagonist and attenuated by a non-NMDA excitatory amino acid receptor antagonist. However, the GABAA-receptor antagonist had no effect on this potentiation. Both intrathecal glutamate (0.1 mM, 2–5 μl it) and NMDA (0.1 mM, 2–5 μl it) induced a potentiation of PPR similar to that of tetanization. Agonist-induced potentiation was shorter than tetanization-induced potentiation. The duration of the contraction wave of intraurethral pressure, elicited by PPR, was elongated by tetanization-induced potentiation, whereas the peak pressure was not affected. All these results demonstrate that brief high-frequency stimulation of the pelvic nerve afferent fiber can induce a distinct and long-lasting modulation in PPR activity and this change may be involved in nociceptive C afferent-induced obstructive urinary dysfunctions.

Although the guinea pig is used widely in experimental medical research, including in studies on micturition control, the spinal origin of preganglionic parasympathetic bladder and somatic external urethral sphincter motoneurons is not known. In the male, guinea pig using wheat germ agglutinin-conjugated horseradish peroxidase and dextran Alexa Fluor((C)) 488/568 tracers, preganglionic parasympathetic bladder motoneurons were observed in the ventrolateral part of the intermediolateral cell group of the first sacral segment. The external urethral sphincter motoneurons were found to be located in the ventral horn of the first sacral segment, in a cell group corresponding with the nucleus of Onuf in cat and human. (C) 2004 Elsevier Ireland Ltd. All rights reserved.

When recording electrical signals from a whole nerve, an increase in the firing frequencies of the fibers contained in the nerve causes an increase in the rectified and time-averaged recorded signal. The latter thus represents superimposed neural activity and can be used for detecting changes in the recorded afferent and/or efferent nerve traffic. The possibility of detecting a fast bladder pressure increase from an increase in the recorded pelvic nerve afferent activity was investigated in this study. Two signal processing approaches were compared: simple discriminant-window thresholding and cumulative sum (CUSUM) algorithm. Both are shown to be able to detect a sudden rise in bladder pressure with the adaptive CUSUM-algorithm being more reliable, but slower.

The objectives of this work were to evaluate the contributions of the ancillary penile nerves to penile erection in male rats in vivo. We investigated the effects of unilateral and bilateral transection of the cavernous nerve (main penile nerve) on the increase in intracavernous pressure (ICP) following electrical stimulation of the medial preoptic area (MPOA) in male rats in vivo. After unilateral or bilateral transection of the cavernous nerve (main penile nerve), the ICP responses showed decreases of 28% and 55%, respectively compared to those ICP responses before transection. In other words, even after bilateral transection of the cavernous nerve, significant increases in the ICP response following central stimulation were observed. In contrast to these findings, the ICP response was completely eliminated following bilateral pelvic nerve transection. These data suggested that the ancillary penile nerves, which originate from the major pelvic ganglia, have a complementary role to the cavernous nerves in the autonomic motor innervation of the penis.

Much attention has been given to the pelvic nerve afferent innervation of the urinary bladder; however, reports differ considerably in descriptions of afferent receptor types, their conduction velocities, and their potential roles in bladder reflexes and sensation. The present study was undertaken to do a relatively unbiased sampling of bladder afferent fibers of the pelvic nerve in adult female rats. The search stimulus for units to be studied was electrical stimulation of both the bladder nerves and the pelvic nerve. Single-unit activity of 100 L6dorsal root fibers, activated by both pelvic and bladder nerve stimulation, was analyzed. Sixty-five units had C-fiber and 35 units had Aδ-fiber conduction velocities. Receptive characteristics were established by direct mechanical stimulation, filling of the bladder with 0.9% NaCl at a physiological speed and by filling the bladder with solutions containing capsaicin, potassium, or turpentine oil. The majority (61) of these fibers were unambiguously excited by bladder filling with 0.9% NaCl and were classified as mechanoreceptors. All mechanoreceptors with receptive fields on the body of the bladder had low pressure thresholds (≤10 mmHg). Receptive fields of units with higher thresholds were near the ureterovesical junction, on the base of the bladder or could not be found. Neither thresholds nor suprathreshold responses could be related to conduction velocity. Bladder compliance and mechanoreceptor thresholds were influenced by the stage of the estrous cycle: both were lowest in proestrous rats and highest in metaestrous rats. Mechanoreceptors innervating the body of the bladder and the region near the ureterovesical junction showed two patterns of responsiveness to slow bladder filling. One group of units exhibited increasing activity with increasing pressure up to 40 mmHg, while the other group showed a peak in activity at pressures below 40 mmHg followed by a plateau or decrease in activity with increasing pressure. It is proposed that differences in stimulus transduction relate to the different response patterns. Thirty-nine units failed to respond to bladder filling. Eight of these were excited by intravesical potassium or capsaicin and were classified as chemoreceptors. The remaining 31 units were not excited by any stimulus tested. Chemoreceptors and unexcited units had both Aδ and C afferent fibers. We conclude that the pelvic nerve sensory innervation of the rat bladder is complex, may be sensitive to hormonal status, and that the properties of individual sensory receptors are not related in an obvious manner to the conduction velocity of their fibers.

After injection of horseradish peroxidase (HRP) into the pelvic nerve of the rat, a small number of HRP-labeled axon terminals were found in the gracile nucleus. Double labeling experiments were also performed: Fluoro-Gold (FG) was injected into the pelvic nerve, while cholera toxin B subunit (CTb) was injected into the gracile nucleus or dorsal faciculus at the fifth and sixth cervical cord segments ipsilateral to the FG injection. About 5% of FG-labeled neurons were labeled with CTb in the L6-, S1- and S2-dorsal root ganglia ipsilateral to the tracer injection. The results suggest that some primary afferent information from pelvic visceral organs may be directly conveyed to gracile nucleus by the primary afferent neurons.

Su, X. and G. F. Gebhart. Mechanosensitive pelvic nerve afferent fibers innervating the colon of the rat are polymodal in character. J. Neurophysiol. 80: 00–00, 1998. This report describes the chemical and thermal sensitivity of mechanosensitive pelvic nerve afferent fibers innervating the colon of the rat. A total of 51 fibers in the S1 dorsal root, identified by electrical stimulation of the pelvic nerve, were studied. An approximately 7 cm length of descending colon was isolated in situ to permit intracolonic perfusion and distension with Krebs solution. Reproducibility of responses to repetitive colorectal distension (CRD, 40 mmHg, 30 s, every 4 min) was documented. All fibers gave monotonic, incrementing responses to graded CRD (5 to 60 mmHg). Increases ( n = 6) or decreases ( n = 6) in pH of the perfusate failed to produce any change in resting activity or responses to CRD. Infusion of bile salts increased the resting activity of 6/6 fibers in a concentration-dependent manner, but did not affect the magnitude of responses to CRD. After intracolonic instillation of an inflammatory soup (bradykinin 10−5M, PGE210−5M, serotonin 10−5M, histamine 10−5M and KCl 10−3M), 13/22 fibers exhibited sensitization of responses to CRD. Seventy-three percent of 45 fibers tested responded to intracolonic perfusion of heated Krebs solution. The estimated threshold for response was 45°C and response magnitude increased with the temperature. A smaller proportion (30%) of 37 fibers tested responded to intracolonic perfusion of cold Krebs solution. The estimated threshold for response was 28°C. Of 36 fibers tested, 8 were activated by both heat and cold; typically, fibers activated by heat did not respond to cold. In a sample of 26 fibers tested for response to all three modalities of stimulation, 11 responded to mechanical, chemical and thermal stimuli; the remaining 15 responded to mechanical and either chemical or thermal stimulation. Changes in intracolonic pressure in response to chemical and thermal stimuli were also evaluated. Inflammatory soup and bile salts did not change intracolonic pressure; heat and cold produced a modest decrease and increase in muscle tension, respectively. These results document that mechanosensitive pelvic nerve afferent fibers are also chemosensitive and/or thermosensitive, supporting the notion that visceral mechanoreceptors in general are likely polymodal in character.

Previous research has demonstrated that anorectal contractions in the rat are modulated by activation of spinal autonomic circuits. In the present study, anterograde tracing of descending pathways originating from the caudal nucleus raphe obscurus (nRO) revealed that this nucleus projects to cells within the intermediolateral (IML) cell column of the thoracic cord and the sacral parasympathetic nucleus (SPN). These anatomical studies suggested that the nRO may influence the regulation of spinal reflexes of the pelvic floor. In a second set of experiments, acute rat preparations were used to investigate changes in anorectal motility during electrical stimulation of the nRO. Anorectal contractions were measured by a fluid-filled manometer. Electrical stimulation of the nRO significantly reduced spontaneous anorectal activity when compared to baseline contractions recorded for 1 min prior to stimulation. Stimulation sites outside the nRO did not affect anorectal contractions when compared to either (a) the 1-min pre-stimulation baseline for that site or (b) the 1-min stimulation period for sites within the nRO. Stimulation of caudal portions of the nRO were more likely than the rostral nRO to reduce anorectal contractions. Given that the SPN contains preganglionic neurons which may be involved in control of anorectal contractions (mediated via the pelvic nerve), the studies presented here suggest a functional role for nRO regulation of preganglionic motoneurons innervating the distal gut of the rat.

The present work is a study of the plastic capacity of the peripheral nervous system subjected to different aggressions in the case of 28 rats of the Wistar breed. They were divided into four groups: 1) sympathetic deafness (n=9); 2) parasympathetic deafness (n=9); 3) evaluation of regeneration (n=9); 4) control group (n=5). An image analyser was used to study the acetilcholinesterase (AChE) and Tiroxine Hidroxilase (TH) positive ganglionic neurones of the pelvic ganglion (GP) as well as the dorsal ganglions (GRD) compared with the control group. With group 3 a study was also made of the possible plasticity of the transacted axons using a wheat germ agglutinin conjugated-horseradish peroxidase (WGA-HRP) neurotracer. The statistical study was carried out by means of the analysis of variance (ANOVA), Fisher test and Scheffe method, with a p < 0.05 taken as significant. The results show the predominant role of the pelvic nerve in the modulation of the plastic changes produced at the ganglionic level, with a lesser influence of the hypogastric nerve. Further studies are needed in order to define the specific role of each of these in the act of miction.

To investigate the role of the pelvic nerve pathway in stress-induced acceleration of colorectal transit and defecation in rats.Surgical transection of rectal nerves (rectal branches of the pelvic nerve), vagotomy (Vag) or adrenalectomy (Adx) were performed bilaterally in rats. Number of fecal pellet output of these rats was measured during 1-h water avoidance stress (WAS). To evaluate the colonic transit, rats were given phenol red through the catheter indwelled in the proximal colon and subjected to WAS. After WAS session, entire colon and rectum were isolated and distribution of phenol red was measured. Distal colonic and rectal transit was evaluated using glass bead. Rats were inserted the glass bead into the distal colon and evacuation rate of the bead was measured. Neural activation was assessed by immunohistochemical staining of c-Fos and PGP9.5 in colonic whole-mount preparations of longitudinal muscle myenteric plexus (LMMP).In the sham-operated rats (sham op), WAS significantly increased defecation and accelerated colorectal transit with marked elevation of plasma corticosterone level. Compared with sham-operated rats, increase in the excretion of fecal pellets during WAS was significantly reduced by rectal nerve transection (RNT) (sham op: 6.9 ± 0.8 vs RNT: 4.3 ± 0.6, P0.05) or Vag (sham op: 6.4 ± 0.8 vs Vag: 3.7 ± 1.1, P0.05), although corticosterone level remained elevated. Adx-rats significantly increased the defecation despite the lower corticosterone level. Distribution pattern of phenol red showed RNT inhibited distal colonic and rectal transit accelerated by WAS, while Vag inhibited proximal colonic transit. Suppression of distal colonic and rectal transit by RNT was further confirmed by the bead evacuation rate (sham op: 80.0% vs RNT: 53.8%). WAS significantly increased the number of c-Fos-immunoreactive neural cells in the LMMP of the proximal and distal colon, whereas c-Fos expression was decreased by RNT in the distal colon (sham op: 9.0 ± 2.0 vs RNT: 4.4 ± 1.0, P0.05) and decreased by Vag in the proximal colon.Pelvic nerve conveys WAS stimuli from the brain to the distal colon, and directly activate the myenteric neurons, followed by the increase of its motility.

The anterior major pelvic ganglion (AMPG) of the male guinea pig possesses a substance P (SP)-immunoreactive peri-neuronal plexus. Selective nerve transections involving the principal inputs of the AMPG, the hypogastric and pelvic nerves, indicate that the SP-immunoreactive peri-neuronal plexus is derived from multiple sources: an extrinsic source involving both the hypogastric and pelvic nerves, and another source (possibly the projections of small intensely fluorescent cells). SP-immunoreactivity (IR) is not normally present in the neuronal perikarya of the AMPG. Evidence is presented that suggests the absence of SP-IR is due to an active suppression of SP-synthesis. This seems to be achieved by a trans-synaptic mechanism involving the hypogastric nerve which, after transection, leads to the appearance of neuronal perikarya exhibiting SP-IR (less than 1% of the total neuronal population of the AMPG). Up to 65% of the neuronal perikarya of the AMPG have the ability to synthesize SP, as demonstrated by SP-IR after 24 h in vitro. A more potent factor in the down-regulation of SP synthesis seems to be exerted by the pelvic genito-urinary organs, especially the prostate.

Using a previously developed canine model of erection, we measured pudendal artery and venous flow as well as pressure in the corpora cavernosa, glans penis, pudendal artery and vein. Penile erection was induced by pelvic nerve stimulation. Arterial flow increased by a factor of 2.5 within two seconds after the onset of stimulation. This was followed by a similar increase in venous flow about one second later. Spongiosal pressure began to rise about six seconds after nerve stimulation and always remained below cavernosal pressure. Cavernosal pressure began to rise after a latency of about 11 seconds. This latency period is accounted for by relaxation of the smooth muscle of the cavernosal sinusoids. Spongiosal pressure is maintained primarily by a high flow state through the glans penis while cavernosal pressure depends on a veno-occlusive mechanism.

The distribution and morphology of preganglionic neurons in the sacral parasympathetic nucleus (SPN) of the cat have been studied with the horseradish peroxidase (HRP) tracing technique. HRP applied to the cut pelvic nerve was identified in cells located ipsilaterally, primarily in the intermediate gray matter. They formed a column approximately 10 mm long, usually contained within two, but occasionally three, sacral segments, S2 contained a majority of cells. In transverse sections the SPN had the appearance of an inverted "L". Cells were medium-sized, oval or spindle-shaped, and transversely oriented. They were distributed among two major components and one minor one: (1) dorsal band (34%) located mainly in lamina V beneath the dorsal horn (cells and dendrites horizontally oriented), (2) lateral band (64%) along the lateral edge of the gray matter in laminae VII through V (cells oriented dorsoventrally with dendrites extending within the nucleus and into the dorsolateral funiculus), and (3) a small group (2%) of cells at the rostral end of the SPN in lamina VII in the middle of the ventral horn. These data coupled with the results of other investigations indicate that the SPN has a viscerotopic organization wherein the colon is innervated primarily by cells in the dorsal band and the urinary bladder is innervated primarily by cells in the lateral band.

The aim of this study was to obtain a measure of the interactions through exclusively spinal circuits, of myelinated afferents with sympathetic preganglionic neurons. Experiments were performed on 16 unanesthetized cats rendered insensitive by bilateral vertebral and carotid occlusion, whose spinal cords had been transected at C1 6-12 h before recording. The evoked responses of 68 tonically active sympathetic preganglionic neurons were recorded from filaments dissected from the cervical sympathetic trunk. Excitation, inhibition and excitation-inhibition sequences were evoked by electrical stimulation of radial, femoral and pelvic nerve afferents. Inhibition was most often observed during pelvic nerve stimulation. Ninety percent of the sympathetic preganglionic neurons tested responded to radial, 77% to femoral and 85% to pelvic nerve stimulation. These differences in percentage of units responding to the three nerves were statistically insignificant. Thus, in the acute spinal cat, the fraction of tonically active sympathetic preganglionic neurons whose activity can be influenced by myelinated afferents is independent of the length of the intraspinal pathway which conveys the input. A main difference between the long pathway (mediating the responses to femoral or pelvic nerve) and the short pathway (mediating the responses to radial nerve) seems to be the efficacy of their connections. While single shocks reliably evoked responses from the radial nerve, trains (200 Hz, 20 msec) were usually necessary to elicit responses from femoral or pelvic nerve, indicating a requirement for summation in the long pathway.

The pelvic nerve in the rat was exposed to HRP in order to localize the cells of origin of preganglionic fibers coursing in this nerve. Labeled cells were located in spinal segments L6-S1, primarily in the lateral intermediate gray. Occassionally, an HRP-filled cell was observed in the ventral horn in association with somatic motoneurons.