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The inhibitory co-receptor programmed death 1 (PD-1, encoded by pdcd1) and its two ligands PD-L1 and PD-L2 comprise an important immune inhibitory signaling pathway for defense against microbes and for self-tolerance. Unlike other members of the B7-CD28 family, expression of PD-L1 and PD-L2 is not limited to the immune system. In this study, we determined that a polyclonal antibody (pAb) (R&D Systems) against extracellular domains of mouse PD-L2 (mPD-L2) could recognize antigen(s) in diverse mouse tissues, including the anterior and intermediate pituitary gland, olfactory bulbs and olfactory epithelium, tongue epithelium, keratinized epithelial cells and skin and whisker hair follicles. These findings differed from previous reports of mPD-L2 localization. Reverse transcription PCR and Western blot analyses, however, were unable to detect any mPD-L2 transcripts or proteins of the 25-kD predicted molecular weight in RNA and protein extracts, respectively, from the above tissues, suggesting that the anti-mPD-L2 pAb cross-reacts with certain novel antigen(s). Developmental studies revealed that the earliest expression of mPD-L2-like antigen was in the olfactory epithelium at embryonic day 12.5 (E12.5). At E14.5, mPD-L2-like antigen was present in the skin, tongue and follicles of the skin and whiskers. The distribution patterns of mPD-L2-like antigen remained similar from E18.5 to adulthood. The results of bioinformatic analysis and other experiments suggested neural cell adhesion molecule and hemicentin-1 as candidate proteins with cross-reactivity to the anti-mPD-L2 pAb. These results demonstrate that care is required in interpreting staining patterns generated when anti-PD-L2 pAb is used to locate PD-L2-expressing cells in the central nervous system and epithelial tissues, such as the olfactory epithelium. In addition, this anti-PD-L2 pAb may be used as an alternative antibody for labeling the olfactory epithelium during embryonic development in mice.

A gain-of-function study showed that miR-7a promoted the generation of oligodendrocytes (OL) and retained the cells in their precursor stage. Inhibiting miR-7a reduced oligodendrogenesis but expanded neuronal population. miR-7a might exert these effects by repressing the expression of proneural genes and regulators for OL differentiation.

ZnO Calthrop-like framework have been synthesized via a microwave assisted way by thermal decomposition of precursors in the ionic liquid 1-butyl-3-ethyl imidazolium tetrafluoroborate ([Beim]BF4) aqueous solution. The structure of [Beim]BF4 were analyzed by means of IR and 1HNMR, The as-samples were characterized by XRD, SEM and UV techniques. The results showed that the as-prepared ZnO have wurtzite structure. nanorods have a diameter of 50 nm to100 nm and lengths of about 3 μm , and the ionic liquid [Beim]BF4 can not only act as a reaction medium but also modify ZnO nanorods in the reaction. The growth mechanics of ZnO nano-structure was preliminary studied.

The dry chemical method is developed to fabricate CuO nanostructures via microwave assisted irradiation in ionic liquid 1-butyl-3-ethyl imidazolium tetrafluoroborate ([BMIM][BF4]). Both nanoparticles (20 nm in size) and nanorods (10-20 nm in diameter and 100-200 nm in length) of monoclinic CuO were obtained. The as samples were characterized by FTIR, XRD, TEM, SADE. The morphologies of the nanostructures can be controlled by the amount-tuning of NaOH and ionic liquids. The growth mechanism of CuO nanostructures is investigated.

Bentonite has been regarded as buffer material for high-level radioactive waste (HLW) disposal all over the world, plenty of decay heat released from HLW is conducted through butter material, therefore, thermal conduction of compacted bentonite is very important. This study presents compacted GMZ Na-bentonite(with 8.9% water content, 1.8 g/cm3 compacting density) temperature and relative humidity change pattern with time and position variation taking intermittent warming method and using thermal conduction equipment, it is designed according to the conceptual model of HLW geological disposal repository. The results show that the temperature achieve a balance quickly, the temperature of compacted bentonite block which the distance is 2 cm to heat source reaches the first about 55˚C balance stage after about 40 hours, radial temperature gradient (GT) increases with the temperature rising, average of GT during the first stage is 0.85˚C/cm, average of GT during the second balance stage about 82˚C is 1.57˚C/cm; Affected by temperature, relative humidity increase rapidly at the beginning with the temperature rising, when the temperature reaches equilibrium, the relative humidity decreases slowly, the higher temperature of the compacted bentonite block is, the lower relative humidity is, the radial gradient of relative humidity (GHR) increase with heating time, average of GHR during the first stage about 55 ˚C is 1.32%/cm, average of GHR during the second stage about 82˚C is 1.89 %/cm.

Titanate modified bentonite could catalyze methane into synthesis carbon nanotubes at high temperature by thermal chemical vapor deposition. The element iron contained in bentonite acts as the catalytic metal of nanotubes. A conclusion was drawn that the quality and quantity of carbon nanotubes were best and largest respectively at 800 ℃. If the temperature is higher than 900 ℃,the quality of nanotubes would be bad. The catalytic capacity of modified bentonite would disappear below 700 ℃. The catalyst is cheaper, and the treatment process of the catalyst is simpler than traditional metal catalyst , which may accelerate industrial synthesis of carbon nanotubes.

Abstract: Astrocytes constitute a major class of glial cells in the CNS, and play crucial roles in physiological functioning, performance and maintenance of the CNS, as well as promotion of neuronal migration and maturation. Astrocytes have also been directly and indirectly implicated in the pathophysiology of various trauma occurrences, development of neurodegenerative diseases and nerve regeneration. To further understand mechanisms by which astrocytes elicit these effects, the first critical step in the study of astrocytes is the preparation of purified astrocytes cultures. Here we describe a simple and convenient procedure for producing rat primary astrocyte cultures of high purity, viability and proliferation. For astrocyte culture, we have optimized the isolation procedures and cultivation conditions including coating substrates, enzyme digestion, seeding density and composition of the culture medium. Using immunofluorescent antibodies against GFAP and OX-42 in combination of Hoechst 33342 fluorescent staining, we found that the purity of the astrocyte cultures was >99%. Astrocytes had high viability as measured by 3-(4, 5-dimethyl-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay. In addition, flow cytometric analysis was used to measure and observe variations in the cell cycle after 1–2 passages and proliferation of astrocytes was detected with a high percentage of cells stand in S+G2/M phase. Therefore, the method described here is ideal for experiments, which require highly pure astrocyte cultures.

Nogo-66 receptor was first identified in neurons. Recently, it was demonstrated in glial cells as well. Our previous study on the expression of Nogo-66 receptor in the cerebellum of the rat surprisingly found its location at the glial gap junctions. Here, we present our study on Nogo-66 receptor in the rat posterior pituitary, which is densely packed with pituicytes, a special type of astrocyte, and is known to be rich in gap junctions. We were able to demonstrate with immunohistochemistry and immuno-electron microscopy abundant Nogo-66 receptor immunoreactive gap junctions between pituicytes. This study, together with our prior one, strongly suggests that the Nogo-66 receptor may play a role in regulating the function of the gap junctions.

The carotid body (CB) senses changes in arterial blood PO2and modulates respiratory movement. It is generally accepted that the dopaminergic type I cells in the CB are chemoreceptors. However, it has not been clarified whether the carotid body has the ability to perceive the stimulation of proinflammatory cytokines. Interleukin 6 (IL-6) as a multifunctional cytokine plays a pivotal role in host defense mechanism. In the present study, we observed the expression of IL-6Ra mRNA and protein in the carotid body using immunohistochemistry, Western blots, and in situ hybridization. The results confirmed the presence of IL-6Ra proteins and mRNAs in the glomus cells of rat carotid body. These results suggest that the function of the carotid body may be influenced by the proinflammatrory cytokines through their receptors. © 2006 Wiley-Liss, Inc.

Mab35 is a monoclonal antibody against one specific immunogenic region in 1, 3, 5 subunits of nicotinic acetylcholine receptors (N-AChR) of a variety of species. It has previously been claimed that N-AChR-like immunoreactivity (-LI) identified by mab35 is present in vasopressin-containing magnocellular neurons. However, we show here by double immunofluorescence labelling that mab35 immunoreactivity is predominantly localized to oxytocinergic rather than vasopressinergic magnocellular neurons. We further infer that mab35 predominantly stained the 3 andor 5 subunits in rat oxytocinergic neurons, and suggest that the unbalanced distribution of these subunits may contribute to some specific physiological properties of oxytocinergic neurons.

The current study was designed to locate the neuronal activation in rat brain following intraperitoneal injection of Staphylococcusenterotoxin B (SEB) and observe the consequence of preliminary subdiaphragmatic vagotomy on SEB-induced brain Fos expression to clarify the role of the vagus nerve in sensation and transmission of abdominal SEB stimulation. The results showed that intraperitoneal SEB (1 mg/kg) induced a robust Fos expression in widespread brain areas. A significant increase of Fos immunoreactive cells were observed in the solitary tract nucleus, locus ceruleus, lateral parabrachial nucleus, ventrolateral part of central gray, medial amygdaloid nucleus, central amygdaloid nucleus, ventromedial part of thalamus, dorsomedial part of thalamus, hypothalamic paraventricular nucleus, lateral habenula, and lateral septum nucleus following SEB challenge. In hypothalamic paraventricular nucleus, in addition to the dense Fos expression in the parvocellular portion, some Fos-positive cells were also observed in the anterior magnocellular nucleus of the complex. Double immunofluorescence studies showed that these Fos-immunoreactive cells were mostly oxytocinergic. The results also showed that subdiaphragmatic vagotomy largely attenuated, but not totally abrogated, the brain Fos expression induced by abdominal administration of SEB. Our data suggest that peripheral SEB stimulation can induce activation of neurons in widespread brain areas and that the vagus plays a crucial role in transmitting the signal of abdominal immune stimulation to the brain.

Nogo‐A is known to be a myelin‐associated protein with strong inhibitory effect on neurite outgrowth and has been considered one of the major factors that hinder fiber regeneration in the central nervous system. Recent studies have demonstrated widespread occurrence of nogo‐A mRNA and Nogo‐A protein in neurons. Our concurrent immunohistochemical study substantiated the widespread distribution of neuronal Nogo‐A. The present study was thus focused on its intraneuronal distribution in the central nervous system, using Western blotting, immunohistochemical, and immunogold electron microscopic techniques. Western blotting of the nucleus, cytoplasm, and membrane subcellular fractions of the cerebellum and spinal cord tissues demonstrated that all three fractions contained Nogo‐A. Nogo‐A immunoreactivity could be identified under confocal microscope in the nucleus, perikayon, and proximal dendrite and along the cell membrane. Under the electron microscope, the perikaryonal Nogo‐A immunogold particles were mainly distributed at polyribosomes and rough endoplasmic reticulum, suggesting its relationship with translation process. The immunogold particles could also be found beneath or on the plasma membrane. In the nucleus, the Nogo‐A immunogold particles were found to be localized at the chromatins of the nucleus, indicating its possible involvement in gene transcription. The presence of Nogo‐A in the nucleus was further supported by transfection of COS‐7L cells with nogo‐A. This study provides the first immunocytochemical evidence for intraneuronal distribution of Nogo‐A. Apparently, the significance of Nogo‐A in the central nervous system is far more complex than what has been envisioned. J. Comp. Neurol. 458:1–10, 2003. © 2003 Wiley‐Liss, Inc.

We explored the possibility of cytochrome oxidase (CO) involvement in spinal cord regeneration in adult rats. The spinal cord was hemitransected at T9. After one month's survival, the animals were deeply anesthetized and perfused. The spinal cord segments including the lesion site were removed and sectioned horizontally for CO histochemistry. Under light microscope, a substantial number of CO-reactive nerve fibers and boutons were identified in the lateral funiculus adjacent to the lesion site. Under electron microscope, moderately to highly CO-reactive mitochondria could be seen within nerve fibers and boutons. Synaptic contacts were identified among them. The increase in CO activity in nerve fibers and boutons may indicate their high-energy demand for synaptic and spontaneous activity following spinal cord hemisection.

The pre-Bötzinger complex (PBC), thought to be the center of respiratory rhythm generation, is a cell column ventrolateral to the nucleus ambiguus. The present study analyzed its cellular and neurochemical composition in adult rats. PBC neurons were mainly oval, fusiform, or multipolar in shape and small to medium in size. Neurokinin-1 receptor, a marker of the PBC, was present in the plasma membrane of mostly medium and small neurons and their associated processes and boutons. Among neurons immunoreactive for different neurotransmitter or receptor candidates, various numbers were colocalized with neurokinin-1 receptor. The highest ratio was with nitric oxide synthase (52.72%), and the lowest was with glycine receptors (31.93%). Glutamic acid decarboxylase- and glycine transporter 2-immunoreactive boutons, as well as GABAAreceptor-immunoreactive plasma membrane processes and boutons, were also identified in the PBC. PBC neurons exhibited different levels of cytochrome oxidase activity, indicating their various energy demands. Our results suggest that synaptic interactions within the PBC of adult rats involve a variety of neurotransmitter and receptor types and that nitric oxide may play an important role in addition to glutamate, GABA, glycine, and neurokinin.

The present study investigated the role of reactive oxygen species (ROS) in activation of nuclear factor of activated T cells (NFAT), a pivotal transcription factor responsible for regulation of cytokines, by vanadium in mouse embryo fibroblast PW cells or mouse epidermal Cl 41 cells. Exposure of cells to vanadium led to the transactivation of NFAT in a time- and dose-dependent manner. Scavenging of vanadium-induced H2O2withN-acety-l-cyteine (a general antioxidant) or catalase (a specific H2O2inhibitor) or the chelation of vanadate with deferoxamine, resulted in inhibition of NFAT activation. In contrast, an increase in H2O2generation by the addition of superoxide dismutase or NADPH enhanced vanadium-induced NFAT activation. This vanadate-mediated H2O2generation was verified by both electron spin resonance and fluorescence staining assay. These results demonstrate that H2O2plays an important role in vanadium-induced NFAT transactivation in two different cell types. Furthermore, pretreatment of cells with nifedipine, a calcium channel blocker, inhibited vanadium-induced NFAT activation, whereas A23187and ionomycin, two calcium ionophores, had synergistic effects with vanadium for NFAT induction. Incubation of cells with cyclosporin A (CsA), a pharmacological inhibitor of the phosphatase calcineurin, blocked vanadium-induced NFAT activation. All data show that vanadium induces NFAT activation not only through a calcium-dependent and CsA-sensitive pathway but also involved H2O2generation, suggesting that H2O2may be involved in activation of calcium-calcineurin pathways for NFAT activation caused by vanadium exposure.

Arsenic compounds are a somewhat unique class of metals, which have been considered as both carcinogens and chemotherapeutic agents for cancers. Tumor promotion effects of arsenic are believed to be associated with its transactivational activities on transcription factors, such as AP‐1 and NFκB, while the induction of cell apoptosis and differentiation by arsenic is considered to be a mechanism for the chemotherapeutic effects of arsenic. Here, we found that exposure of cells to arsenite and arsenate leads to transactivation of retinoic acid response elements (RARE) and glucocorticoid response elements (GRE) in mouse epidermal JB6 cells. These inductions occur in a time‐dependent manner. Furthermore, induction of RARE activity by arsenic was synergistically enhanced by co‐treatment of cells with retinoic acid, while GRE activation by arsenic was not affected by combined treatment of cells with fluocinolone acetonide (FA). In consideration of the important role of RARE and GRE in induction of cell differentiation, we speculate that transactivation of RARE and GRE by arsenic may be involved in its induction of cell differentiation and anti-cancer activities in addition to its induction of apoptosis.

Cadmium is a potent and effective carcinogen in rodents and has recently been accepted by IARC (International Agency for Research on Cancer) as a category 1 carcinogen. Cadmium-induced up‐regulation of intracellular signaling pathways leading to increased mitogenesis is thought to be a major mechanism for the carcinogenic activity following chronic cadmium exposure. In the present study, we found that exposure of cells to cadmium induced significant activation of AP‐1 and all three members of the MAP kinase family in mouse epidermal JB6 cells. The induction of AP‐1 activity by cadmium appears to involve activation of Erks, since the induction of AP‐1 activity by cadmium was blocked by pretreatment of cells with PD98058. Interestingly, the induction of AP‐1 by cadmium was greatly enhanced by the chemical tumor promoter, TPA and the growth factor EGF, but not by ultraviolet C radiation. In vivostudies demonstrated that cadmium could also induce transactivation of AP‐1 in AP‐1‐luciferase report transgenic mice. Considering the role of AP‐1 activation in tumor promotion, the results presented in this study provide a possible molecular mechanism for cadmium‐induced carcinogenesis.

Tumor promoting effects of arsenic are believed to be associated with its transactivation activity on transcription factors, such as AP‐1 and NFκB. However, the results from different groups studying the effects of arsenic on NFκB activation are contradictory in different cell models. Since arsenic is a strong skin carcinogen, we have investigated the activation of NFκB by arsenic in a mouse skin epidermal cell line, JB6 cells. Exposure of cells to arsenite or arsenate led to NFκB transactivation in mouse epidermal JB6 NFκB‐luciferase reporter stable transfectants, C141 NFκB mass1. This induction of NFκB activity by arsenic was dose‐ and time‐dependent. The transactivation of NFκB by arsenic appeared to be through activation of Erks and JNKs pathways because increased NFκB activity by arsenic could be dramatically inhibited by either pre‐treatment of cells with PD98059 or overexpression of dominant negative JNK1. That Erks activation is required for arsenic‐induced NFκB transactivation was further supported by the findings that arsenic‐induced NFκB transactivation was impaired in JB6 30.7b cells, which were deficient in Erks.

In the present study we show that, in contrast to the rat, injection of cholera toxin B‐subunit (CTB) into the intact sciatic nerve of Macaca mulattamonkey gives rise to labelling of a sparse network of fibers in laminae I–II of spinal cord and of some mainly small dorsal root ganglion (DRG) neurons. Twenty days after sciatic nerve cut, the percentage of CTB‐positive lumbar 5 (L5) DRG neuron profiles increased from 11% to 73% of all profiles. In the spinal cord, a marked increase in CTB labelling was seen in laminae I, II, and the dorsal part of lamina III. In the rat L5 DRGs, 18 days after sciatic nerve cut, the percentage of CTB‐ and CTB conjugated to horseradish peroxidase (HRP)‐labelled neuron profiles increased from 45% to 81%, and from 54% to 87% of all neuron profiles, respectively. Cell size measurements in the rat showed that most of the CTB‐positive neuron profiles were small in size after axotomy, whereas most were large in intact DRGs. In the rat spinal dorsal horn, a dense network of CTB‐positive fibers covered the whole dorsal horn on the axotomized side, whereas CTB‐labelled fibers were mainly seen in laminae III and deeper laminae on the contralateral side. A marked increase in CTB‐positive fibers was also seen in the gracile nucleus. The present study shows that in both monkey and rat DRGs, a subpopulation of mainly small neurons acquires the capacity to take up CTB/CTB‐HRP after axotomy, a capacity normally not associated with these DRG neurons. These neurons may transganglionically transport CTB and CTB‐HRP. Thus, after peripheral axotomy, CTB and CTB‐HRP are markers not only for large but also for small DRG neurons and, thus, possibly also for both myelinated and unmyelinated primary afferents in the spinal dorsal horn. These findings may lead to a reevaluation of the concept of sprouting, considered to take place in the dorsal horn after peripheral nerve injury. J. Comp. Neurol. 404:143–158, 1999. © 1999 Wiley‐Liss, Inc.

Galanin can normally be detected only in a few dorsal root ganglion (DRG) neurons, but it is dramatically upregulated after peripheral nerve injury in both rat and monkey. Galanin is stored in large dense core vesicles, which after axotomy are often found close to the membrane of afferent nerve endings in the dorsal horn. In the monkey there is an increase in galanin in many ner ve terminals in the superficial dorsal horn after axotomy, but such an inc rease is more difficult to detect in the rat. Galanin is also present in local dorsal horn neurons, where it is upregulated by peripheral inflammation. Both galanin-R1 and galanin-R2 receptor mRNAs are expressed in rat DRGs, mainly in, respectively, large and small DRG neurons. Galanin-R1 receptor mRNA is downregulated in DRG neurons after axo-tomy, and a small decrease in galanin-R2 receptor mRNA levels can also be seen. After peripheral tissue inflammation galanin-R1 receptor mRNA levels decrease and galanin-R2 receptor mRNA levels increase. The present results show that galanin and galanin receptors are present in sensory and local dorsal horn neurons and are regulated by nerve injury and inflammation. Galanin may therefore be involved in processing of pain information, primarily exerting analgesic effects. Whereas local dorsal horn neurons represent a defense system against inflammatory pain, we have proposed that a second defense system, against neuropathic pain, is intrinsic to DRG neurons.

Opioid peptides have profound inhibitory effects on the production of oxytocin and vasopressin, but their direct effects on magnocellular neuroendocrine neurons appear to be relatively weak. We tested whether a presynaptic mechanism is involved in this inhibition. The effects of μ-opioid receptor agonist d-Ala2, N-CH3-Phe4, Gly5-ol-enkephalin (DAGO) on excitatory and inhibitory transmission were studied in supraoptic nucleus (SON) neurons from rat hypothalamic slices using whole cell recording. DAGO reduced the amplitude of evoked glutamatergic excitatory postsynaptic currents (EPSCs) in a dose-dependent manner. In the presence of tetrodotoxin (TTX) to block spike activity, DAGO also reduced the frequency of spontaneous miniature EPSCs without altering their amplitude distribution, rising time, or decaying time constant. The above effects of DAGO were reversed by wash out, or by addition of opioid receptor antagonist naloxone or selective μ-antagonist Cys2-Tyr3-Orn5-Pen7-NH2(CTOP). In contrast, DAGO had no significant effect on the evoked and spontaneous miniature GABAergic inhibitory postsynaptic currents (IPSCs) in most SON neurons. A direct membrane hyperpolarization of SON neurons was not detected in the presence of DAGO. These results indicate that μ-opioid receptor activation selectively inhibits excitatory activity in SON neurons via a presynaptic mechanism.

Fos oncoprotein expression has been shown to be a sensitive marker for sequential neuronal activation in response to a specific stimulus. The present study investigated the effect of the γ‐aminobutyric acid (GABA)‐A receptor agonist muscimol on kainic acid (KA)‐induced limbic seizures and Fos expression in the rat forebrain. One hour after KA injection, a substantial Fos expression was observed in the hippocampal dentate gyrus, whereas only a low level of Fos induction was seen in CA1–3 fields. Six hours post‐injection a prominent increase of Fos expression occurred in most forebrain structures, including the whole hippocampus. Following 0.5 mg/kg muscimol treatment a remarkable decrease of Fos expression occurred but only in the caudate putamen and core of the accumbens nucleus. Treatment with 1 mg/kg muscimol led to further significant decreases of Fos expression in CA1–3 pyramidal neurons and the disappearance of Fos induction in the cerebral cortex above the rhinal fissure, reticular thalamic nucleus, claustrum, fundus striati, ventral pallidum, septal nucleus, lateral habenular nucleus, and lateral amygdaloid nucleus. When 2 mg/kg muscimol was injected, animals exhibited ‘absence seizures’ instead of limbic seizures, and Fos expression in the hippocampus was effectively blocked. These results suggest that a reduction of GABAergic inhibition plays a crucial role not only in limbic seizure genesis in the dentate gyrus, but also in the seizure spread mechanism in many brain structures, among which the hippocampal CA1–3 fields are most markedly involved, less marked in the cerebral cortex and some other structures, and least marked in the caudate putamen and core of the accumbens nucleus.

USING the model of gamma–hydroxybutyrate (GHB)–induced generalized absence epilepsy, the present work investigated the distribution of fos oncoprotein expression in the rat thalamus with fos antibody immuno–histochemistry. Thirty minutes after absence-like seizures, some fos-immunoreactive cell nuclei were found in bilateral thalamic paraventricular nuclei (PV). After a further 30 min, a massive bilateral induction of fos was observed in the lateral habenular nucleus (LHb), the PV, the rhomboid thalamic nucleus, and the intralaminar nuclei of the thalamus. These results suggest that the LHb and the midline and intralaminar thalamic nuclei may very likely be involved in the pathophysiology of absence seizures.

The pars distalis of the anterior pituitary is known to be regulated by hypothalamic hormones. Recently, we have discovered the presence of substance P-like immunoreactive nerve fibers in the pars distalis of the monkeys. Substance P-like immunoreactivity in the pars distalis of the dog was investigated in this study. A substantial amount of substance P-like immunoreactive nerve fibers with a large amount of varicosities were found. They were widely distributed in the gland, more abundant along its periphery. Most of them were closely related to the glandular tissue, some were located on vascular walls. Substance P-like immunoreactive nerve fibers were also found in the meningeal sheath of the anterior pituitary. They could be followed into the parenchyma of the gland.

The presence of abundant nitric oxide synthase (NOS) in magnocellular neurons of the rat hypothalamus suggests that nitric oxide (NO) may be involved in controlling the release of oxytocin and vasopressin. To test this possibility, we examined the effect of NO-related drugs on extracellular discharges of 124 supraoptic nucleus (SON) neurons from slices of rat hypothalamus in vitro. Twenty-three (43%) of 53 neurons were inhibited by sodium nitroprusside (SNP), a spontaneous releaser of NO, at 1–3 mM. This inhibition was prevented by preincubation of the slices with 1 μM hemoglobin, an inactivator of NO (n= 14), whereas hemoglobin alone enhanced neuronal activity in seven (35%) of 20 neurons. l-Arginine (1 mM), a precursor of NO, inhibited neuronal activity in five (36%) of 14 neurons, while d-arginine (1 mM), the inactive counterpart of l-arginine, was ineffective (n= 12). N-ω-nitro-l-arginine methyl ester (l-NAME, 10 μM), an inhibitor of NOS, also enhanced neuronal activity in five (29%) of 17 neurons, while N-ω-nitro-d-arginine methyl ester (DNAME, 10 μM), the inactive enantiomer of l-NAME, was without effect (n= 11). Together, our data show that NO exerts predominantly an inhibitory effect on SON neurons and may serve as a negative feedback loop in controlling release of oxytocin and vasopressin.

The mammalian anterior pituitary was not known to be innervated other than by a few autonomic nerve fibers. Recent studies, however, have demonstrated otherwise. A hypothesis of neural-humoral dual regulation of the mammalian anterior pituitary has been postulated based on the following findings: (1) the presence of substantial amounts of nerve fibers in the anterior pituitary of a number of mammalian species; (2) close contact of the nerve fibers with the gland cells, even forming synapses; (3) the nerve fibers originate, as least partly, from the hypothalamus; (4) the nerve fibers respond actively to changes in hormonal levels of the organism; and (5) stimulation of the nerve fibers changes the secretory activities of the gland cells. Microsc. Res. Tech. 39:131–137, 1997. © 1997 Wiley-Liss, Inc.

There is evidence suggesting cross-talk among gland cells of the anterior pituitary. We had reported a rare form of synaptoid contact between corticotrophs in the anterior pituitary of the dog. We then found similar synaptoid contacts with different characteristics in the rat, as described in the present article. Male Sprague-Dawley rats were used. The anterior pituitaries were prepared for ultrastructural study of substance P immunoreactivity of the anterior pituitary. Routine preembedding immunohistochemical staining was conducted, the sections were embedded in Epon 812 (Serva Feinbiochemica, Heidelberg, New York), and ultrathin sections were prepared. In the anterior pituitary of the rat, synaptoid contacts were found between corticotrophs and lactotrophs. They appeared very close to typical synapses in the central nervous system, aside from evident weakness of presynaptic density. The presence of synaptoid contacts suggests a form of cross-talk between the gland cells in the anterior pituitary of the rat. Anat. Rec. 251:181–184, 1998. © 1998 Wiley-Liss, Inc.

The mammalian anterior pituitary was not known to be innervated other than by a few autonomic nerve fibers. Recent studies, however, have demonstrated otherwise. A hypothesis of neural‐humoral dual regulation of the mammalian anterior pituitary has been postulated based on the following findings: (1) the presence of substantial amounts of nerve fibers in the anterior pituitary of a number of mammalian species; (2) close contact of the nerve fibers with the gland cells, even forming synapses; (3) the nerve fibers originate, as least partly, from the hypothalamus; (4) the nerve fibers respond actively to changes in hormonal levels of the organism; and (5) stimulation of the nerve fibers changes the secretory activities of the gland cells. Microsc. Res. Tech. 39:131–137, 1997.© 1997 Wiley‐Liss, Inc.

PERIPHERAL axotomy of the spinal nerve and avulsion of the ventral roots have been found to induce increase in expression of nitric oxide synthase (NOS) in the spinal motor neurones and the dorsal root ganglion. The present study investigated changes of NOS, using NADPH-diaphorase (NADPH-d) reactivity as the marker, in vagal complex after axotomy in the rat. Eight days after left cervical vagotomy the NADPH-d reactivity was found to be markedly enhanced in the dorsal motor nucleus of the vagus nerve, the ambiguus nucleus, the solitary tract and the nucleus of the tractus solitarius, and the nodose ganglion. This study offers the first evidence of changes in NOS expression in cranial visceral components following axotomy.

Our previous studies have shown the presence of substantial amounts of substance P and calcitonin gene-related peptide-like immunoreactive nerve fibres in the anterior pituitary of the monkey, dog and rat. Furthermore, synaptic relationships have been demonstrated between these nerve fibres and the gland cells in the dog and rat. The substance P and calcitonin gene-related nerve fibres increase in number following adrenalectomy and ovariectomy, respectively. The present study was aimed to investigate the galanincontaining nerve fibres in the anterior pituitary of normal and adrenalectomized rats. The results showed only a small amount of galanin-like immunoreactive nerve fibres in the normal anterior pituitary, which were present among the gland cells as well as along the blood vessels. Following adrenalectomy, the number of galanin-like immunoreactive nerve fibres increased and ramification appeared more frequently. The results substantiate our hypothesis of a dual neural-humoral regulation of the mammalian anterior pituitary gland.

The mammalian anterior pituitary has recently been shown to be innervated by substantial amounts of peptidergic nerve fibres. It has also been found that adrenalectomy increases the amount of calcitonin gene‐related peptide‐like immunoreactive nerve fibres in the anterior pituitary of the rat, and that stimulation of the nerve fibres in vitro can enhance release of ACTH. In the present study, the density of substance P‐like immunoreactive nerve fibres in the anterior pituitary of the rat were examined in relation to variations in plasma oestrogen status. The amount of substance P‐like immunoreactive nerve fibres increased significantly (P<0.001) after ovariectomy, and decreased significantly (P<0.01) under oestrogen replacement, in a dose‐dependent manner. The results suggest the possibility of the direct neural involvement of oestrogen secretion in anterior pituitary regulation, which further substantiates the hypothesis of neural‐humoral dual regulation of the mammalian anterior pituitary.

It has been reported that inosine has no direct neuroprotection against respiratory inhibitors due to the absence of purine nucleoside phosphorylase in neurons. Recent evidence, however, has shown that inosine has direct neurotrophic effects. Thus, lack of direct neuroprotection, as reported before, may not be a general conclusion, but is related to special types of injury. We used PC12 cells to explore direct neuroprotection of inosine against high concentration of zinc sulfate, an injury different from the previous one and found that inosine reduced the mortality of PC12 cells significantly in a dose dependent manner. The results indicate that inosine can directly protect neurons from zinc-induced injury, and such effect might be mediated via mechanism(s) other than purine nucleoside phosphorylase.

Sphingosine 1-phosphate stimulates the mobilization of EGFR ligands to drive eyelid closure in rat embryos.