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Background: Atopic dermatitis (AD) is a chronic, inflammatory, often severely itching skin disorder. It may worsen due to stress, depression, or anxiety. Calcitonin gene-related peptide (CGRP) may be involved in inflammation signaling. CGRP has also been suggested in relation to stress, depression, and anxiety. This study aimed to investigate the expression of CGRP in the skin of patients with AD., Methods: Twenty-seven adult patients with AD, characterized with clinical and psychodemographic parameters, were investigated regarding CGRP expression in skin biopsies, using an immunohistochemical technique., Results: The total number of CGRP-positive nerve-like fibers was found to be higher in lesional skin than in non-lesional skin. Moreover, more inflammatory cells of dendritic shape intruded into the epidermis in lesional skin compared to non-lesional skin. Keratinocytes showing expression of CGRP were also found in lesional skin. Interestingly, the number of CGRP-positive nerve-like fibers in lesional skin correlated with depressive and anxiety scores. Correlation with depressive score was also found for round CGRP-positive inflammatory cells in the epidermis., Conclusions: CGRP may have a role in both the inflammatory process and distress, in AD.

Calcitonin gene-related peptide (CGRP) concentrations are increased in postmenopausal women and castrated men with symptomatic flushing. We wanted to determine if a CGRP increase exists in the plasma of healthy fertile-age women during sweating. Plasma concentrations of CGRP were measured by radioimmunoassay at maximal sweating during a sauna session and during bicycle exercise both at maximal and 70% of maximal work capacity in 8 healthy women of fertile age. Plasma concentrations of CGRP were unaffected (>90% statistical power) during both experimental sessions. We suggest that sweating itself does not explain the rise in CGRP concentrations observed in flushing postmenopausal women., (Copyright (c) 2005 S. Karger AG, Basel.)

We investigated whether the sensory neuropeptide, calcitonin gene-related peptide (CGRP), could be synthesised by human lymphocytes. Our results indicate that in activated B-cells, there is a strong expression of CGRP gene transcripts, which is almost absent in resting cells. Since B-cells autocrinally produce NGF, the neutralisation of endogenous NGF by anti-NGF antibodies resulted in a marked reduction in CGRP expression in both resting and activated B-cells. Thus, NGF appears to directly affect the synthesis of CGRP in B-cells as in sensory neurons. By regulating CGRP synthesis in lymphocytes and neuronal cells, NGF can influence the intensity and duration of the immune response.

Purpose: In women the vasodilatory neuropeptides calcitonin gene-related peptide and neuropeptide Y seem to be involved in menopausal hot flashes. We assessed whether plasma calcitonin gene-related peptide and neuropeptide Y change during hot flashes in men after castration., Materials and Methods: We evaluated 10 men 61 to 81 years old who underwent castration due to cancer of the prostate and had frequent hot flashes for changes in plasma calcitonin gene-related peptide and neuropeptide Y during 1 day at the outpatient clinic. At least 5 blood samples were obtained between flashes and 4 were obtained during each flash. The samples were analyzed for calcitonin gene-related peptide and neuropeptide Y using radioimmunoassay technique. Hot flashes were objectively recorded by measuring peripheral skin temperature and skin conductance., Results: Plasma calcitonin gene-related peptide increased 46% (95% confidence interval 21 to 71) during flashes in the 6 men in whom it was measurable. This change was statistically significant (p = 0.028). The concentration of neuropeptide Y was below the detection limit. Skin conductance and temperature increased significantly during flashes., Conclusions: Calcitonin gene-related peptide is involved in the mechanisms of hot flashes in men who underwent castration due to prostate carcinoma. Thus, there may be a similar mechanism of hot flashes in women and in men deprived of sex steroids.

Objective: The majority of men who undergo surgical or medical castration due to prostatic carcinoma develop vasomotor symptoms with hot flushes. The mechanisms behind these symptoms are poorly understood. One possible explanation is a release of the vasodilatory peptide calcitonin gene-related peptide (CGRP) from perivascular nerves, which seem to be involved in the mechanisms behind vasomotion and sweating in postmenopausal women. The aim of this report was to investigate whether CGRP is involved in vasomotion in men after castration therapy., Material and Methods: Twenty-four hour urine excretion of CGRP was analysed in 15 men with prostatic carcinoma, using radioimmunoassay before and 3 months after surgical or medical castration., Results: Eleven of the 15 men developed hot flushes during the observation period of 3 months. Twenty-four hour urine excretion of CGRP did not change significantly after castration, either in the group as a whole or in those 11 men who developed hot flushes., Conclusions: Even though we did not observe any significant changes in 24-h urine excretion of the potent vasodilator CGRP after castration it is possible that serum levels of CGRP increase during hot flushes, without having an effect on the 24-h urine excretion of the peptide.

The aim of the present study was to investigate the influence of an exercise program on neuropeptide concentrations, disease activity, impairments and disabilities in rheumatoid arthritis (RA). Eleven females (median age 60 years, median disease duration 6.5 years, ARA functional classes I or II) exercised 30 min daily for 4 weeks. The urine concentrations of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) and neuropeptide Y-like immunoreactivity (NPY-LI) were analyzed 1 week prior to exercise start, at exercise start, after 2 and 4 weeks of exercise, and after a 4-week follow-up period. Measurements of disease activity, aerobic capacity, grip force, limb muscle function, and activities of daily living (ADL) were also undertaken. The results indicate a decrease (md 5.64 pM to md 3.48 pM, P

Over the last decade, several patients afflicted with xerostomia have been treated with acupuncture. Their salivary flow rates increased significantly and the improvement lasted during a long observation period. We also found that the release of several neuropeptides in the saliva of healthy subjects can be increased by acupuncture stimulation. The concentration of vasoactive intestinal polypeptide increased significantly in the saliva of xerostomic patients after acupuncture treatment. The release of the neuropeptide calcitonin gene-related peptide (CGRP) was investigated in the saliva of xerostomic patients in order to elucidate further the mechanisms of the effect of sensory stimulation (acupuncture) on the salivary secretion. CGRP-like immunoreactivity was measured with radioimmunoassay (RIA) before and after a double series of acupuncture treatment, in stimulated saliva of 14 patients who suffered from xerostomia. The results showed that the concentration of CGRP increased significantly (P<0.001) in the saliva of these patients after the end of acupuncture treatment as compared to base-line levels. Taking into consideration the influence of CGRP on the salivary flow, as well as its trophic effect, we concluded that the increased release of CGRP could be one of the factors that affect positively the salivary flow rates of xerostomic patients who were treated with acupuncture., (Copyright 1999 Harcourt Publishers Ltd.)

Objectives: To establish whether 24 h urinary excretion of the potent vasodilator calcitonin gene-related peptide (CGRP) was higher in postmenopausal women with vasomotor symptoms compared to the level in women without symptoms. We also wanted to establish whether urinary excretion of CGRP changed during the menstrual cycle in women of fertile age., Material and Methods: Thirteen postmenopausal women with and 13 women without vasomotor symptoms were included. Urine was collected over 24 h and CGRP excretion was measured utilizing radio-immunoassay technique. Twenty-four hour CGRP excretion was also measured in ten fertile women with regular cycles in early follicular, preovulatory and midluteal phase., Results: Twenty-four hour urinary excretion of CGRP was significantly higher in women with vasomotor symptoms compared to non-flushing women (median 7.16 vs 5.15 pmol/24 h; P = 0.028). CGRP concentrations were stable throughout the ovulatory cycles., Conclusion: The 24 h urinary excretion of CGRP is higher in women with vasomotor symptoms than in women without these symptoms. CGRP may be the mediator of vasodilator signals originating from the thermoregulatory center.

The contribution of calcitonin gene-related peptide (CGRP) to bilateral oedema formation in the rat hindpaw following an unilateral challenge with CGRP was investigated. Rats were injected into the left hindpaw with either saline, CGRP or a CGRP antagonist (CGRP8-37). All injections were given in a double blind fashion and in a volume of 100 microl. CGRP and CGRP8-37 were administered in concentrations of 75, 150 or 300 pmol. Volumes of the right and left hindpaw were measured every hour for 5 h by plethysmometry. Injection of CGRP 300 pmol into the left hindpaw resulted in a bilaterally increased hindpaw volume after 5 h as compared with the groups given saline. No changes were found in hindpaw volumes following the injection of either 75 or 150 pmol of CGRP or 75, 150 or 300 pmol of CGRP8-37 as compared with saline injection. To elucidate whether or not the bilateral oedema formation was related to a release of endogenous CGRP, microdialysis of the contralateral hindpaw was carried out, and concentrations of CGRP-like immunoreactivity (-LI) were determined by radioimmunoassay and high performance liquid chromatography. Injection of CGRP 300 pmol into the left hindpaw increased the release of CGRP-LI into the right hindpaw perfusate after 4 and 5 h. No changes in CGRP-LI were detected in the right hindpaw perfusate following challenge with saline or CGRP8-37. To study the contribution of the nervous system to the contralateral release of CGRP-LI, sciatic nerve ligated and intact sham-operated rats were used. Sciatic nerve ligation but not sham-operation on the non-injected side abolished the increased release of CGRP-LI following contralateral administration of CGRP 300 pmol. To study the spinal cord mechanisms resulting in the bilateral oedema formation following unilateral challenge with 300 pmol of CGRP, intrathecal pretreatment with either 10 nmol bicuculline (GABA(A) receptor antagonist) or 10 nmol CGRP8-37 was carried out. Bicuculline but not CGRP8-37 abolished the bilateral oedema formation induced by CGRP 300 pmol. In order to study the mechanisms by which administration of CGRP 300 pmol induces oedema, CGRP 300 pmol was administered concomitantly with either 300 pmol of CGRP8-37 (CGRP receptor antagonist), or 3 nmol of promethazine (H1 receptor antagonist), or 3 nmol of s(-)-propranolol (5-HT1 receptor antagonist), or 3 nmol of cyproheptadine (5-HT2 receptor antagonist) or 3 nmol of ICS 205-930 (5-HT3 receptor antagonist). Oedema formation was measured at 1, 5, 7 and 24 h. Injection of CGRP 300 pmol into the left hindpaw induced a bilateral oedema formation which was still significant at 24 h. Concomitant administration of either CGRP8-37, ICS 205-920 or cyproheptadine blocked the oedema formation at 24 h. No effect on oedema formation was found when CGRP 300 pmol was co-administered with either promethazine or s(-)-propranolol (H1 and 5-HT1 receptor antagonists, respectively). The results of the present study show that both the nervous system and local inflammatory processes contribute to bilateral hindpaw oedema formation following unilateral challenge with CGRP 300 pmol. Our results indicate that endogenous release of CGRP following inflammatory response may play an important role in inducing oedema formation.

The expression of the sensory neuropeptide calcitonin gene-related peptide (CGRP) in the skin, secondary lymphoid organs and dorsal root ganglia (L4-L6) in Leishmania major-induced inflammation was evaluated by radioimmunoassay. The investigation was conducted on two mouse strains, the susceptible BALB/c and the resistant C57BL/6. The CGRP concentration in the inflamed skin of both mouse strains was decreased as early as 1 week postinfection, compared to controls. A further reduction was observed in both mouse strains throughout the 9-week study period, but was more evident in the susceptible strain. The CGRP concentration was increased in the ipsilateral dorsal root ganglia (L4-L6) of mice of the resistant strain 1 week postinfection, while no change was observed in the susceptible strain. In the remaining part of the study period there was a reduction in CGRP in the ipsilateral dorsal root ganglia of both mouse strains. In the spleen, a reduction was noted in the infected BALB/c at all measurement times (significant at 6 and 9 weeks), while no change was observed in C57BL/6 strain. These findings may indicate a regulatory function of CGRP in the pathophysiology of murine cutaneous leishmaniasis and hence in the disease outcome. The reduction in CGRP might also explain the defective nociception observed in patients with cutaneous leishmaniasis.

The effects of experimentally induced ischaemia after free-flap surgery on concentrations of neuropeptide Y (NPY), neurokinin A (NKA), substance P (SP) and calcitonin gene-related peptide (CGRP)-like immunoreactivity (-LI) were studied in flap tissue and in different regions of the rat brain (striatum, hippocampus, pituitary, hypothalamus, frontal and occipital cortex). Ten days after the operation, CGRP-LI and NKA-LI were decreased in the ischaemic tissue but increased in the surrounding tissue. In the brain, CGRP-LI was increased in five of six regions analysed, with the exception of the striatum. SP-LI and NKA-LI were increased in the pituitary and hippocampus, but decreased in other brain regions. Changes of CGRP-LI in the brain correlated positively with the CGRP-LI concentrations in the surrounding flap tissue and the CGRP-LI concentrations in the ischaemic flap tissue with the extent of flap survival. The results of the present study suggest that higher concentrations of CGRP-LI are related to tissue survival and that endogenous CGRP has a regulatory effect in ischaemia.

The present study was performed to explore the modulatory potential of different endogenous opioid systems on transmission of presumed nociceptive information at the spinal cord level in thermally injured rats. Thermal injury was performed by dipping the left paw into water 60 degrees C for 20 s. This induced a significant bilateral decrease in hindpaw withdrawal latency HWL to pressure. Intrathecal administration of 10 nmol of CGRP8-37 induced a significant bilateral increase in HWL in the thermally injured group and in the intact controls. The effect of different opioid receptor antagonists on the increased latency to withdrawal response induced by intrathecal injection of 10 nmol of CGRP8-37 was explored in the thermally injured rats. The effect was reversed by intrathecal injection of 40 and 80 nmol of: b-funaltrexamine (mu opioid receptor antagonist) and naltrindole (delta opioid receptor antagonist), but not by norbinaltorphimine (kappa opioid receptor antagonist). The results of the present study show that intrathecal CGRP8-37 increases hindpaw withdrawal latency in thermally injured rats, an effect reduced by a mu as well as by a delta opioid receptor antagonist.

Calcitonin gene-related peptide (CGRP) is a very potent vasodilator in the nervous system, and may be involved in hot flushes experienced by most women around menopause. Flushing post-menopausal women had higher urinary excretion of CGRP before than after successful treatment of their flushes with acupuncture. The prevalence of vasomotor symptoms is lower in physically active women. In a rat model we therefore intended to assess whether acupuncture and exercise affected CGRP concentrations in different parts of the brain and peripherally. The aim of the study was to elucidate the short- and long-term effects of exercise and acupuncture on CGRP concentrations in the nervous system of normal adult rats. In a rat model, we examined the effects of single interventions and long-term treatment with physical exercise and manual or electro-acupuncture on CGRP concentrations in urine, cerebrospinal fluid and serum and different parts of the brain. In all compartments studied, but significantly only in the cerebrospinal fluid, CGRP increased after a single session of physical exercise or electro-acupuncture. Manual acupuncture did not change CGRP concentrations in any compartment. Rats had the highest concentrations of CGRP in the pituitary and hypothalamus but the concentrations did not differ significantly between control rats and those subjected to long-term treatment with manual or electro-acupuncture or running rats. Rats treated with electro-acupuncture had twice the CGRP concentration in the frontal cortex compared to control rats, albeit the difference did not reach statistical significance. Evidently manual and electro-acupuncture have different effects, whereas electro-acupuncture and physical exercise have more similar effects on CGRP production and/or release. To elucidate the role of CGRP in vasomotor symptoms, further studies with older flushing rats should be performed.

The present study was performed to explore the effects of intrathecal administration of calcitonin gene-related peptide8-37 (CGRP(8-37)) on the hindpaw withdrawal latency (HWL) to pressure in rats with one thermally injured hindpaw. Furthermore, the interaction of CGRP(8-37)and naloxone was studied. Thermal injury was performed by dipping the left paw into 60 degrees C for 20 s. This induced a significant increase in the volume of the left hindpaw (P<0.001) and significant bilateral decreases of the latency of hindpaw withdrawal response to mechanical stimulation (Left: P<0.001; right: P<0.05). Intrathecal administration of 10, 20 and 40 nmol of CGRP(8-37), but not of 1 or 5 nmol, induced a significant bilateral increase in HWLs (P<0.001). The effect of CGRP(8-37) was partly reversed by intrathecal injection of naloxone at a dose of 32 and 64 microg respectively. Using radioimmunoassay, we found a significant bilateral increase in the concentration of CGRP-like immunoreactivity in the perfusate of both hindpaws 24 h after unilateral thermal injury (left: P< 0.001; right: P< 0.05). There was also an increase in the amount of CGRP-like immunoreactivity in the cerebrospinal fluid (P< 0.001), but not in plasma. The results indicate that CGRP plays a role in the transmission of nociceptive information in the spinal cord of thermally injured rats. Furthermore, our findings suggest that opioids can modulate CGRP-related effects in the spinal cord.

Rats were pretreated with 0.9% NaCl, or 0.1 or 1.0 mg/kg MK-801, an anticonvulsant and a psychotomimetic drug, and 60 minutes later given ECS or sham ECS. After six sessions the animals were sacrificed and neuropeptide Y (NPY-), neurokinin A (NKA-), and calcitonin gene-related peptide (CGRP-) like immunoreactivity (-LI) measured with radioimmunoassays. ECS increased NPY-LI in frontal cortex, striatum, occipital cortex and hippocampus, and NKA-LI in occipital cortex and hippocampus. MK-801 increased CGRP in a dose-response manner in frontal cortex, and NKA-LI in occipital cortex. Although the higher MK-801 dose reduced seizure duration by 50%, the ECS induced NPY-LI increase in striatum, occipital cortex and hippocampus, and NKA-LI in occipital cortex was not diminished. In contrast, there was a parallel decrease in seizures and NPY-LI and NKA-LI changes in frontal cortex and hippocampus, respectively. Investigation of neuropeptides in brain may contribute to understanding of the mechanisms of action of antidepressive and antipsychotic treatments and of psychotomimetic drugs.

Ischemia resulting from flap harvesting and vascular manipulation during microsurgery may be responsible for flap ischemic sufferance and, ultimately, necrosis. Recently, the regulatory role of the sensory nervous system in ischemia has attracted much interest. Calcitonin gene-related peptide (CGRP), a neuropeptide, is a naturally occurring vasodilator with no constrictive effects. In the present study, we developed a model of partial, chronic ischemia in the rat epigastric flap and investigated the effects of ischemia on concentrations of CGRP-like immunoreactivity (-LI) in ischemic skin and in different regions of the rat brain (striatum, hippocampus, pituitary, hypothalamus, and frontal and occipital cortex). A neurovascular island flap based on the superficial epigastric vessels was raised in 10 animals. Ischemia of the flap was obtained by ligating the feeding artery so that the blood flow was reduced to 25% of the normal circulation. An electromagnetic Doppler positioned on the artery was used to monitor the blood flow reduction. Ten nonoperated animals were used as controls. Ten days after the operation, CGRP-LI was significantly increased in five of six brain regions analyzed (striatum excepted). Significantly decreased concentrations of CGRP-LI were found in seven ischemic flaps, as opposed to the control group. In the remaining three flaps, no significant changes in CGRP concentration were observed. The highest blood flux values (detected using a laser Doppler) in the flaps correlated positively with the highest concentrations of CGRP-LI in the flap tissue. The results of the present study suggest that endogenous CGRP may be involved in the adaptive response to ischemia.

1. Recent work in our laboratory has demonstrated that intrathecal administration of a selective antagonist of calcitonin gene-related peptide (CGRP), CGRP8-37, increased the hindpaw withdrawal latency (HWL) to thermal stimulation and hindpaw withdrawal threshold (HWT) to pressure in normal rats, and that these effects were more pronounced than in rats with mononeuropathy. 2. The present study was performed to investigate the effects of intrathecal administration of CGRP8-37 on the HWL and HWT in rats with unilateral hindpaw inflammation induced by subcutaneous injection of carrageenin. The effect of naloxone was also studied. 3. Subcutaneous injection of 0.1 ml of carrageenin into the plantar region of the left hindpaw induced a significant increase in the volume of the ipsilateral hindpaw (P < 0.001), and significant bilateral decreases of the HWL to thermal stimulation (ipsilateral: P < 0.001; contralateral: P < 0.01) and HWT to pressure (ipsilateral: P < 0.001; contralateral: P < 0.01). 4. Intrathecal administration of 10 nmol of CGRP8-37, but not of 1 or 5 nmol, induced a significant bilateral increase in the HWL and HWT in rats with experimentally induced inflammation (thermal test: P < 0.001; mechanical test: P < 0.001). 5. The effect of intrathecal administration of 10 nmol CGRP8-37 on HWL and HWT was significantly more pronounced in intact rats than in rats with experimentally induced inflammation (ipsilateral: P < 0.001; contralateral: P < 0.001). 6. The effect of CGRP8-37 on withdrawal responses in the inflamed paw was partly reversed by intrathecal injection of naloxone at a dose of 88 nmol in the thermal (ipsilateral: P < 0.01; contralateral: P = 0.14) and mechanical tests (ipsilateral: P < 0.05; contralateral: P = 0.60). 7. A significant bilateral increase in the concentration of CGRP-like immunoreactivity in the perfusate of both hindpaws was demonstrated 24 h after unilateral injection of carrageenin (ipsilateral: P < 0.001; contralateral: P < 0.05). There was also an increase in the amount of CGRP-like immunoreactivity in the cerebrospinal fluid (P < 0.001), but not in plasma (P = 0.75). 8. The present study demonstrates that acute experimentally-induced unilateral hindpaw inflammation, induces bilateral increases in the amount of CGRP-like immunoreactivity in hindpaw perfusates. Intrathecal administration of CGRP8-37 increased the HWL to thermal stimulation and HWT to pressure bilaterally. 9. The results indicate that CGRP plays a role in the transmission of presumed nociceptive information in the spinal cord of rats with experimentally induced inflammation. Furthermore, our findings suggest that opioids can modulate CGRP-related effects in the spinal cord.

Objective: To analyze the occurrence of substance P (SP) and calcitonin gene-related peptide (CGRP) in ankle joints and corresponding dorsal root ganglia (L2-L6) of rats with adjuvant arthritis., Methods: Arthritis was induced by inoculation with heat-killed mycobacteria. The morphologic distribution of SP and CGRP was assessed by immunohistochemical analysis. Tissue concentrations of the neuropeptides were determined by radioimmunoassay., Results: Neuronal CGRP-like immunoreactivity was clearly increased in the synovium and the dorsal root ganglia, whereas the increase in SP-positive structures was less pronounced. The tissue concentrations of SP and CGRP were significantly increased both in ankle joints and in dorsal root ganglia., Conclusion: Levels of sensory neuropeptides are increased under conditions of joint inflammation.

Forty-one patients (37 female and four male) with signs and symptoms of temporomandibular joint arthritis, were separated into two diagnostic groups (group I: inflammatory; group II: degenerative/non-specific joint disease). They were examined clinically, fluid was aspirated from the joint with saline and venous blood samples were collected at the same time. The joint fluid and plasma samples were analysed for neuropeptide-like immunoreactivity, i.e. neuropeptide Y (NPY-LI), calcitonin gene-related peptide (CGRP-LI), substance P (SP-LI) and neurokinin A (NKA-LI), using competitive radioimmunoassays. The aim was to investigate any co-variation of the peptides in the joint fluid and plasma. In group I, the median values of peptide concentrations in joint fluid were SP-LI = 129, CGRP-LI = 75, NKA-LI = 36 and NPY-LI = 676 pmol/l and in group II, SP-LI = 52, CGRP-LI = 64, NKA-LI = 45 and NPY-LI = 318 pmol/l. There were no significant differences between the groups for peptide concentrations. In group I, all the neuropeptides were strongly correlated. In group II, SP-LI and NKA-LI were strongly correlated while CGRP-LI was weakly correlated with NPY-LI and NKA-LI. Multiple step-wise regression analysis showed that most of the variation in NPY-LI, CGRP-LI and SP-LI in group I was explained by NKA-LI, but the regression did not reach statistical significance in group II.

The effects of capsaicin on the sensory neuropeptides substance P and calcitonin gene-related peptide were analyzed in the ankle joints and dorsal root ganglia (L2-L6) of adult female Lewis rats. The study included 23 normal rats and 23 arthritic rats, all injected subcutaneously with capsaicin (total dose 200 mg/kg bw). Another two groups of animals from a previous study, i.e., 23 normal rats and 23 arthritic rats not given capsaicin served as controls. Adjuvant arthritis was induced by inoculation with heat-killed mycobacteria. The morphological distribution of sensory neuropeptides was assessed by immunohistochemistry and the tissue concentrations were determined by radioimmunoassay. In normal rats, capsaicin significantly reduced the concentrations of substance P and calcitonin gene-related peptide in ankle joints (54 and 36%, respectively) as well as dorsal root ganglia (40 and 54%, respectively). In arthritic rats those pretreated with capsaicin had significantly lower concentrations of substance P and calcitonin gene-related peptide in dorsal root ganglia (19 and 42%, respectively) compared to the arthritic controls. In the ankle joints, however, only the SP concentration was reduced (42%). Notably, this was accompanied by a 40% reduction in inflammatory response as assessed by comparing the ankle joint weights of the experimental groups. In general, there was a good correlation between the neuropeptide concentrations in ipsilateral ankle joints and the corresponding dorsal root ganglia as assessed in individual rats. The present study of adjuvant induced arthritis shows that capsaicin administration reduces the otherwise up-regulated levels of sensory neuropeptides in dorsal root ganglia and ankle joints. However, capsaicin at the dose given can only mitigate, not completely prevent the development of joint inflammation. Nonetheless, the findings suggest that antineuronal therapy targeted against specific neurotransmitters may prove useful in inflammatory joint disease.

The occurrence of substance P (SP) and calcitonin gene-related peptide (CGRP) was assessed in the ankle joints and dorsal root ganglia (L2-L6) by immunohistochemistry and radioimmunoassay (RIA) after unilateral sciatic nerve section in adjuvant arthritis. Nerve section in arthritic rats had no clear-cut effect on warmth, redness, and swelling of ankle joints, but significantly affected the occurrence of SP and CGRP. Immunohistochemical analysis showed an almost complete disappearance of SP-positive fibers in the ipsilateral ankle joint in normal rats after axotomy, whereas in arthritic rats occasional SP-positive fibers remained. In dorsal root ganglia, only occasional SP-positive cells could be detected in normal and arthritic rats after axotomy. A similar but somewhat less pronounced effect of axotomy was noted for neuronal CGRP-LI. RIA showed a decrease in SP in ankle joints by 45% in normal rats and 58% in arthritic rats; the decrease in CGRP was 41% and 47%, respectively. In dorsal root ganglia, the decrease in SP after surgical denervation was 25% in normal rats and 54% in arthritic rats; the decrease in CGRP was 18% and 27%, respectively. The tissue concentrations of SP and CGRP in ipsilateral ankle joints and dorsal root ganglia were consistently correlated in normal as well as arthritic rats. The present study shows that an interruption of the nerve supply to joints cannot fully prevent the development of arthritis, although it significantly reduces the occurrence of sensory neuropeptides.

Substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivity (-LI) was studied in rats' cerebrospinal fluid (CSF), plasma and synovial fluid (SF) from both knee joints at 2 and 24 h following an intraperitoneal administration of 0.05 ml human recombinant interleukin-1 alpha (i.p. hrIL-1 alpha) or saline. Increased or decreased levels of SP-, NKA and CGRP-LI were detected in CSF and plasma, whereas NPY-LI was unaffected. In SF only CGRP-LI increased bilaterally. There was a correlation in CGRP-LI content between plasma and CSF following i.p. hrIL-1 alpha but not between plasma and SF or CSF and SF. It can be concluded that (1) i.p. hrIL-1 alpha activates somatosensory afferents thereby increasing SP- and CGRP-LI content in CSF and plasma and NKA-LI in CSF; 2) i.p. hrIL-1 alpha induces a bilateral increase of CGRP-LI in SF which is not mediated through systemic circulation and is possibly a part of the general host defensive reaction.

The significance of polyamines for the neoplastic proliferation and secretion of calcitonin (CT) and calcitonin-gene-related peptide (CGRP) by the human medullary thyroid carcinoma TT cell line was investigated. TT cells were cultured in vitro for 6 days with or without additions of pathway inhibitors of polyamine biosynthetic enzymes. Treatment of the cells with 1 mM of the specific L-ornithine decarboxylase (ODC) inhibitor DL-alpha-difluoromethylornithine (DFMO) resulted in a 97% decrease in ODC activity, lowered contents of putrescine (96%) and spermidine (85%) and cell proliferation rates (90%) along with a compensatory 15-fold increase in S-adenosyl-L-methionine decarboxylase (SAMDC) activity. DFMO treatment also led to a decrease in cellular content of CT (33%) and CGRP (26%), while the drug enhanced secretion of CT (31%) but depressed that of CGRP (26%), and elevated the ratio of CT to CGRP secreted into the medium by 74%. Ethylglyoxal bis(guanylhydrazone) (EGBG), a SAMDC inhibitor, at 100 microM evoked a similar reduction of cell proliferation and lowered the content of spermine by 81%. Furthermore, EGBG treatment caused a 34-fold increase in ODC activity and a subsequent 35-fold build-up of putrescine, but also seemed to stabilize SAMDC as evidenced by a highly enhanced SAMDC activity (approximately 200-fold) during enzyme assays in the absence of the inhibitor. EGBG exposure resulted in an increase in cellular CT content (110%) and secretion of the hormone (82%), while not affecting CGRP content or release.2+ EGBG effects were partially counteracted by DFMO.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritic temporomandibular joints were investigated for intra-articular temperature and joint fluid content of calcitonin gene-related peptide. Eleven patients (16 joints) with rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, or chronic unspecific polyarthritis or monarthritis participated in the study. The intra-articular temperature varied between 35.5 and 37.5 degrees C, with a mean of 36.5 degrees C. The concentration of calcitonin gene-related peptide varied between 7.5 and 749.0 pmol/l, with a mean of 108.6 pmol/l. There was a positive correlation between the intra-articular temperature and the joint fluid concentration of calcitonin gene-related peptide. The plasma level of the peptide was on an average 5% of the joint fluid level.

Slices of human iris or ciliary body, obtained post-mortem (8-12 h after death, n = 5), were superfused in vitro with capsaicin (10 microM) and the immunoreactivity for substance P (SP-LI) or calcitonin gene-related peptide (CGRP-LI) was measured in the effluent. In the iris and in the ciliary body CGRP-LI was 3.71 +/- 0.74 pmol/g and 3.01 +/- 0.55 pmol/g and SP-LI was 6.68 +/- 0.75 pmol/g and 6.55 +/- 0.84 pmol/g, respectively. A first exposure to capsaicin increased the CGRP-LI outflow from the ciliary body (427 +/- 46 fmol/g/30 min), whereas a second challenge with the drug 30 min later, failed to significantly enhance the CGRP-LI outflow (21.8 +/- 15.6 fmol/g/30 min). Likewise, the capsaicin-evoked increase in CGRP-LI outflow from the iris slices (472 +/- 62 fmol/g/30 min) was no longer observed at the second drug administration (38.4 +/- 12.8 fmol/g/30 min). Capsaicin failed to increase the SP-LI outflow from either the iris or the ciliary body. Reverse phase HPLC analysis of CGRP-LI indicated that authentic CGRP was contained in the tissue and in the superfusate collected during exposure to capsaicin. The present results show that in the human iris and ciliary body, capsaicin releases CGRP possibly contained in terminals of sensory nerves.

We have measured the endogenous levels of gastric and duodenal calcitonin gene-related peptide (CGRP)-, neurokinin A (NKA)-, galanin-vasoactive intestinal polypeptide (VIP)- and neuropeptide Y (NPY)-like immunoreactivity (li) in relation to cysteamine-induced gastric lesions and duodenal ulcers in rats. CGRP-li but not NKA-, galanin-, VIP- or NPY-li was decreased in gastric and duodenal samples following a single ulcerogenic dose of cysteamine (900 mg/kg p.o.). Temporal relationships of this phenomenon showed that CGRP-li was selectively decreased (stomach 45%, duodenum 68% as compared to controls, respectively after 24 h) concomitantly to the formation of acute gastric lesions and duodenal ulcers. Animals bearing healed ulcers 12 days after cysteamine, had gastroduodenal CGRP-li similar to control values. Pretreatment with the selective sensory neurotoxin capsaicin decreased gastroduodenal CGRP-li but not NKA-, galanin-, VIP- or NPY-li, showing that CGRP might be considered a marker of the afferent innervation of the gastroduodenal tract. The residual gastroduodenal CGRP-li levels in capsaicin-pretreated animals were not decreased by cysteamine administration, indicating that the effect of cysteamine is restricted to a peptide pool of primary afferent origin. Duodenal CGRP-li is selectively decreased by the duodenal ulcerogen cysteamine during the acute phase of ulcers formation and might be among the local mediators which afford protection against the ulcerogenic stimuli.

Electrical field stimulation of circular muscle strips from the guinea-pig isolated renal pelvis produces a frequency-dependent positive inotropic effect of the spontaneous contractions which is unaffected by atropine and guanethidine and abolished by tetrodotoxin or in vitro capsaicin desensitization. Omega conotoxin fraction GVIA markedly inhibited the response to low frequencies of stimulation but had only a partial or minor inhibitory effect at higher frequencies. Tachykinins produce a concentration-dependent positive inotropic effect, neurokinin A being more potent than substance P. On the other hand, rat alpha calcitonin gene-related peptide (CGRP) inhibited spontaneous contractions of the renal pelvis. MEN 10,376 a neurokinin A (4-10) analog, antagonized the positive inotropism produced by neurokinin A, without affecting the response to KCl, and suppressed the positive inotropic response produced by electrical field stimulation. In the presence of MEN 10,376, a negative inotropic response was produced by electrical field stimulation which was antagonized by the C-terminal fragment (8-37) of human alpha calcitonin gene-related peptide (hCGRP). hCGRP (8-37) antagonized the negative inotropic effect of exogenously administered CGRP without affecting inhibition by isoprenaline. Application of capsaicin (10 microM) produced a marked increase in the outflow of substance P-, neurokinin A- and CGRP-like immunoreactivities from the superfused guinea-pig renal pelvis. Substance P-, neurokinin A- and CGRP-like immunoreactivities were also detected in tissue extracts of the renal pelvis by radioimmunoassay. These experiments indicate that peptide release from peripheral endings of capsaicin-sensitive primary afferents represents the major type of nerve-mediated response affecting motility of the guinea-pig isolated renal pelvis. Tachykinins and CGRP act as physiological antagonists and the excitatory action of tachykinins prevails over the inhibitory action of CGRP. Local modulation of renal pelvis motility by sensory nerves could facilitate removal of irritants present in the urine, protecting the kidney during obstruction and ureteral antiperistalsis.

Calcitonin gene-related peptide (CGRP), but not substance P (SP), was found to inhibit edema-promoting actions of inflammatory mediators (histamine, leukotrine B4, 5-hydroxytryptamine) in vivo in the hamster cheek pouch, human skin, and rat paw. The effect of CGRP was present in the low nanomolar dose range, and it was mimicked by activation of sensory nerves with capsaicin which caused release of endogenous CGRP-like immunoreactivity (IR). The findings provide new information on the potential impact of sensory nerve activation during inflammatory processes by indicating that sensory nerves may play an anti-inflammatory role.

To investigate the hypothesis that calcitonin gene-related peptide (CGRP), a potent vasodilator, is an important physiological defence against fluid overload, plasma CGRP concentrations were measured in various degrees of fluid overload in 26 haemodialysis patients, for whom diuresis, mediated by atrial natriuretic peptide (ANP), is not a possible defence mechanism. Plasma CGRP concentrations were positively correlated with the degree of fluid excess (r = 0.815, p = 0.0001) and were significantly higher in 5 patients with severe fluid overload than in those less severely affected (143 [SE 14] vs 52 [11] pmol/l; p less than 0.001). CGRP may be an effective defence against complications of fluid overload since it can increase capitance by vasodilatation.

The peptides galanin (GAL), substance P (SP), and calcitonin gene-related peptide (CGRP) were analyzed with immunohistochemistry and radioimmunoassay in the spinal cord, dorsal root ganglia, dorsal roots, and sciatic nerve of normal rats and rats subjected to several experimental procedures, including ligation, crush, and/or sectioning of nerves. The results show that peripheral nerve transection induces a dramatic increase in GAL content both in dorsal roots and sciatic nerve, demonstrating that this lesion causes an increased out-transport of the newly synthesized peptide both into the central and peripheral branches of the primary sensory neurons. In contrast evidence was obtained for decreased out-transport of SP and CGRP. The functional significance of these findings remains to be analyzed.

Arterial plasma levels and renal venous overflows of immunoreactive neuropeptide Y (NPY-LI) and calcitonin gene-related peptide (CGRP-LI) were studied during mental stress (a modified version of Stroop's colour word conflict test--CWT) and during i.v. infusions of step-wisely increasing doses of adrenaline (ADR) in 12 healthy male volunteers. At rest, mean arterial plasma levels of NPY-LI and CGRP-LI were 27 +/- 2 pmol l-1 and 61 +/- 9 pmol l-1, respectively. No renal venoarterial concentration difference could be demonstrated for either peptide at rest. Although CWT caused a three-fold increase in the simultaneously measured renal venous overflow of noradrenaline, indicating markedly increased renal sympathetic nerve activity, the arterial levels of NPY-LI were unchanged and the net renal overflow of NPY-LI was only slightly (not significant) and transiently increased. CWT also failed to influence CGRP-LI levels in arterial plasma or CGRP overflow from the kidney. During ADR infusions, which increased arterial plasma ADR from 0.25 +/- 0.06 to 6.43 +/- 0.27 nmol l-1, NPY-LI levels were unaffected but CGRP-LI levels in arterial plasma were elevated (P less than 0.001 by ANOVA). No net renal overflow of CGRP-LI could, however, be demonstrated. These findings suggest that CWT is not powerful enough a stimulus to significantly enhance systemic or renal overflows of NPY-LI even though marked renal sympathetic activation occurs. During ADR infusions plasma CGRP-LI levels increased but renal veno-arterial differences of CGRP-LI were unaltered, indicating that CGRP-LI may be released from sites other than the kidney by ADR.

Capsaicin (10(-9) to 10(-5) M) contracted guinea-pig tracheal strips. Epithelium-containing tracheal strips developed a maximum active tension which was significantly higher than that observed in epithelium-free strips. Anti-CGRP (calcitonin gene-related peptide) serum blocked the epithelium-dependent potentiation of the capsaicin-induced contraction in the intact tracheal strips, without affecting the response of the epithelium-free strips. This result suggests the occurrence of an epithelium-dependent release of CGRP. This same serum markedly reduced the contraction induced by exogenous rat CGRP in both intact and epithelium-free tracheal strips. In epithelium-free tracheal strips, capsaicin-induced contraction was abolished by spantide (10(-6) and 10(-5) M), a substance P antagonist, but, in intact tracheal strips, spantide did not abolish the capsaicin-induced contraction, showing that both CGRP and substance P release are directly induced by capsaicin. Moreover, the contractile responses to rat CGRP of intact tracheal strips from guinea pig suggest that CGRP itself might be able to release a contracting factor from the airway epithelium. Therefore, CGRP originating from the airway epithelium may play a major role in the control of airway smooth muscle tone.

Neuropeptides in primary afferent neurons have been found to be engaged in the immediate type of hypersensitivity. However, their role in the delayed form of hypersensitivity is not yet established. The hypothesis that substance P (SP), neurokinin A (NKA), and calcitonin gene-related peptide (CGRP) are involved in delayed hypersensitivity was tested in oxazolone-induced, murine ear allergic contact dermatitis. Concentrations of immunoreactive SP, NKA, and CGRP were measured in extracts of the eczema ears (n = 26), whereas extracts of the opposite ears were used as controls. The SP, NKA, and CGRP contents in the treated ears were on the average 28% (p = 0.001), 32% (p = 0.004), and 15% (p = 0.016), respectively, lower than in the control ears. Lower peptide concentrations in the eczema ears indicate increased release of the peptides because the peptides are rapidly metabolized locally when released and only replenished by axonal transport from the cell bodies. Our results indicate that peptides released from primary afferent neurons play a role in the delayed type of hypersensitivity reactions.

The effects of lithium on brain regional concentrations of substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivities (-LI) were studied in rat. In the pilot study, rats were divided into three groups that were administered vehicle, or 1 or 4 mEq/kg lithium sulphate, respectively, intraperitoneally once/day for 9 days. In the second experiment, rats were divided into three groups receiving vehicle, or 1 or 2 mEq/kg lithium sulphate, respectively, intraperitoneally twice/day for 9 days. After sacrifice by focused microwave irradiation, brains were dissected, weighed, and frozen. Peptides were extracted and measured in extract aliquots by specific radioimmunoassays. Marked regional differences (P less than .001) were found for each of the peptides measured. In the pilot study the higher lithium dose, 4 mEq/kg, significantly raised neuropeptide levels. However, animals receiving this dose also showed signs of toxicity. In the second experiment, lithium increased SP-LI concentrations in striatum and hypothalamus (72 and 29%, P's less than .001 and .05). NKA-LI was also elevated in striatum (44%, P less than .01). CGRP-LI, in parallel to SP-LI, was increased in striatum and hypothalamus (58 and 78%, P's less than .05 and .01). In contrast, lithium decreased CGRP-LI in the pituitary gland (56%, P less than .01). NPY-LI was increased in striatum, and frontal and occipital cortex (30, 66, and 60%, respectively; P's less than .01, .01, and .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Rat trigeminal neurons innervating tooth pulps were retrogradely labelled with fluorogold and analysed enzyme- and immunohistochemically for their content of substance P, calcitonin gene-related peptide, fluoride-resistant acid phosphatase, GM 1 ganglioside, carbonic anhydrase and neurofilament protein. The data showed that both small, medium-sized and large trigeminal neurons were labelled after fluorogold deposition in maxillary molar pulps, with a majority of the cells being medium-sized and large. Less than 2% of the pulpal neurons showed substance P-like immunoreactivity. Fifty-six per cent of the pulpal nerve cells were calcitonin gene-related peptide-positive. These cells were small, medium-sized and large. Only 1% of the fluorogold-labelled cells contained fluoride-resistant acid phosphatase enzyme activity. This paralleled the finding that the pulpal neurons were unstained by Griffonia simplicifolia isolectin I-B4, a plant lectin which preferentially binds to fluoride-resistant acid phosphatase-positive cells. Choleragenoid-like immunoreactivity, which identifies cells with the GM 1 ganglioside receptor, was found in 70% of the fluorogold-labelled pulpal neurons. Approximately 80% of the fluorogold-labelled cells showed RT 97-immunoreactivity. RT 97 labels neurofilament protein and is present in large light primary sensory neurons. No pulpal neurons appeared to contain carbonic anhydrase, as judged from both enzyme- and immunocytochemical observations. The findings suggest that, in the rat, trigeminal tooth pulp neurons, which according to the classical view are nociceptive, form a heterogeneous group of neurons with a minority of small cells which may contain calcitonin gene-related peptide but rarely either substance P or fluoride-resistant acid phosphatase. However, the vast majority of pulpal nerve cells appear to have sizes and cytochemical characteristics which are not generally associated with nociceptive primary sensory neurons.

The authors measured the plasma levels of calcitonin gene-related peptide (CGRP), the most potent vasodilatator known, during sequential ultrafiltration and haemodialysis in 12 patients using a radio-immunoassay method. Mean plasma levels of CGRP were 70.3 +/- 16.5 (mean +/- SE) pmol l-1 at the start of treatment, it increased to 85.3 +/- 17.6 pmol l-1 during ultrafiltration and to 114.5 +/- 25.3 pmol l-1 during dialysis. Systolic blood pressure decreased during haemodialysis. Plasma levels of CGRP were negatively correlated to systolic blood pressure before and at the end of dialysis, and changes in plasma levels of CGRP were strongly correlated to changes in systolic blood pressure. The increase in CGRP levels was not correlated to the fluid removal, toxin removal or changes in osmolality. The increase in plasma levels of CGRP observed during dialysis may be an important cause of dialysis induced vasodilatation and fall in blood pressure.

Abstract: Neuropeptide Y has been implicated in pain modulation and is substantially up-regulated in dorsal root ganglia after peripheral nerve injury. To identify the role of neuropeptide Y after axotomy, we investigated the behavioral and neurochemical phenotype of neuropeptide Y Y1 receptor knockout mice with focus on dorsal root ganglion neurons and spinal cord. Using a specific antibody Y1 receptor immunoreactivity was found in dorsal root ganglia and in dorsal horn neurons of wild-type, but not knockout mice. The Y1 receptor knockout mice exhibited a pronounced mechanical hypersensitivity. After sciatic nerve axotomy, the deletion of Y1 receptor protected knockout mice from the axotomy-induced loss of dorsal root ganglion neurons seen in wild-type mice. Lower levels of calcitonin gene-related peptide and substance P were identified by immunohistochemistry in dorsal root ganglia and dorsal horn of knockout mice, and the axotomy-induced down-regulation of both calcitonin gene-related peptide and substance P was accentuated in Y1 receptor knockout. However, the transcript levels for calcitonin gene-related peptide and substance P were significantly higher in knockout than in wild-type dorsal root ganglia ipsilateral to the axotomy, while more calcitonin gene-related peptide- and substance P-like immunoreactivity accumulated proximal and distal to a crush of the sciatic nerve. These results indicate that the deletion of the Y1 receptor causes increased release and compensatory increased synthesis of calcitonin gene-related peptide and substance P in dorsal root ganglion neurons. Together, these findings suggest that, after peripheral nerve injury, neuropeptide Y, via its Y1 receptor receptor, plays a key role in cell survival as well as in transport and synthesis of the excitatory dorsal horn messengers calcitonin gene-related peptide and substance P and thus may contribute to pain hypersensitivity. [Copyright &y& Elsevier]