Inhibitory effect of somatostatin on the NPY response to insulin-induced hypoglycemia and the role of endogenous opioids

The present study was undertaken in order to establish whether somatostatin (SRIH) is able to modify the neuropeptide Y (NPY) response to insulin-induced hypoglycemia during insulin tolerance test (ITT) in man. In addition, the possible involvement of opioid peptides in the mediation of hypoglycemia and/or SRIH action was investigated. Subjects were injected intravenously with 0.15IU/kg insulin alone (control test) or with SRIH (4.1μg/min/90min), naloxone (10mg in an iv bolus) or the combination of the two substances. Plasma NPY concentrations rose significantly during ITT. The NPY response was significantly reduced by the treatment with SRIH. The administration of naloxone did not modify NPY levels whereas when both SRIH and naloxone were given, NPY response to hypoglycemia did not differ from that observed in the control test. These data demonstrate that SRIH inhibits the NPY response to hypoglycemia. Naloxone-sensitive endogenous opiates do not seem to be involved in the control of hypoglycemia-induced NPY release. In contrast, since naloxone reversed the inhibiting effect of SRIH, an involvement of opioid peptides in the SRIH action may be supposed.     

Colocalization of peptides and a catecholamine-synthesizing enzyme in intramural neurones of the newborn guinea-pig urinary bladder in culture

The patterns of colocalization of somatostatin (SOM), neuropeptide Y (NPY) and the catecholamine-synthesizing enzyme, dopamine beta-hydroxylase (DBH), were examined in intramural neurones in dissociated cell culture preparations from the detrusor muscle of the urinary bladder of the newborn guinea-pig using an elution-restaining immunocytochemical technique. Large numbers of the intramural neurones contained NPY-like (70-85% of the total neuronal population) and SOM-like (60-75%) immunoreactivities, in contrast to a small population (1-6%) of neurones containing immunoreactivity to DBH. Some neurones were immunoreactive to NPY (15-20%) and SOM (5-10%) alone, while 55-70% of the total neuronal population showed immunoreactivity to both NPY and SOM. NPY-like immunoreactive neuronal cell bodies that did not contain SOM were predominantly binucleate, whereas neuronal cell bodies immunoreactive to SOM alone were mainly mononucleate. Although not seen in every culture preparation, neuronal cell bodies containing both NPY-like and DBH-like immunoreactivities were also observed (less than 5% of the total neuronal population), and most, if not all, of these neuronal cell bodies were binucleate. SOM-like and DBH-like immunoreactivities were not seen in the same neuronal cell body throughout this study. These results show that intramural bladder neurones can be divided into distinct subpopulations based upon the coexistence of specific peptides and enzymes, and the possibility that they sustain local integrative and modulatory roles in bladder function is discussed.     

Recombinant Cholinergic Differentiation Factor (Leukemia Inhibitory Factor) Regulates Sympathetic Neuron Phenotype by Alterations in the Size and Amounts of Neuropeptide mRNAs

The cholinergic differentiation factor (CDF) in heart cells is identical to leukemia inhibitory factor (LIF). Recombinant CDF/LIF was shown to alter dramatically neurotransmitter production as well as the levels of several neuropeptides in cultured rat sympathetic neurons. Here it is shown that these changes are likely to be caused by alterations in the mRNA for these proteins and peptides. Growth in 1 nM recombinant CDF/LIF induces mRNA for acetyl CoA: choline-O-acetyltransferase [EC 2.3.1.6; choline acetyltransferase (ChAT)], somatostatin (SOM), substance P, and vasoactive intestinal polypeptide while lowering mRNA levels of tyrosine hydroxylase (EC 1.14.16.2) and neuropeptide Y (NPY). In addition, the sizes of the mRNAs for ChAT, SOM, and NPY are larger after recombinant CDF/LIF treatment.     

Choline acetyltransferase- and peptide immunoreactivity of submucous neurons in the small intestine of the guinea-pig

Summary The peptides cholecystokinin (CCK), neuropeptide Y (NPY), somatostatin (SOM), substance P (SP) and vasoactive intestinal peptide (VIP), and the synthesizing enzyme for acetylcholine, choline acetyltransferase (ChAT) were localized immunohistochemically in nerve cell bodies of the submucous ganglia in the small intestine of the guinea-pig. VIP-like immunoreactivity was found in 45% of submucous neurons. ChAT immunoreactivity was observed in a separate group of nerve cells, which made up 54% of the total population. There were three subsets of neurons immunoreactive for ChAT: (1) ChAT neurons that also contained immunoreactivity for each of the peptides CCK, SOM and NPY, representing 29% of all submucous neurons; (2) ChAT neurons that also contained SP-like immunoreactivity, representing 11% of all submucous neurons, and (3) ChAT cells that did not contain any detectable amount of the peptides that were localized in this study.     

Patterns of co-existence of peptides and differences of nerve fibre types associated with noradrenergic and non-noradrenergic (putative cholinergic) neurons in the major pelvic ganglion of the male rat

Summary The pelvic ganglia supply cholinergic and noradrenergic nerve pathways to many organs. Other possible transmitters are also present in these nerves, including peptides. Multiple labelling immunofluorescence techniques were used in this study of the male rat major pelvic ganglion (MPG) to examine: (1) the peptides present in noradrenergic (tyrosine hydroxylase (TH)-positive) and non-noradrenergic (putative cholinergic) neurons, and (2) the types of peptide-containing nerve fibres closely associated with these two groups of neurons. The distribution of the peptide galanin (GAL) within the MPG was also investigated. All of the TH-neurons contained neuropeptide Y (NPY), but none of the other tested peptides. However, many NPY neurons did not contain TH and may have been cholinergic. TH-negative neurons also displayed vasoactive intestinal peptide (VIP), enkephalin (ENK) or GAL. VIP and NPY formed the most common types of putative cholinergic pelvic neurons, but few cells contained both peptides. Many ENK neurons exhibited VIP, NPY or GAL. Varicose nerve terminals surrounding ganglion cells contained ENK, GAL, somatostatin (SOM) and cholecystokinin (CCK). These peptide-immunoreactive fibres were more often associated with the non-noradrenergic (putative cholinergic) than the noradrenergic neurons; two types (SOM and CCK) were preferentially associated with the non-noradrenergic NPY neurons. GAL was distributed throughout the MPG, in small neurons, scattered small, intensely fluorescent (SIF) cells, and both varicose and non-varicose nerve fibres. The nerve fibres were concentrated near the pelvic and penile nerves; most of the varicose fibres formed baskets surrounding individual GAL-negative somata.     

Neuropeptide Y and vasoactive intestinal polypeptide in cerebral arteries of the rat: relationships between innervation pattern and mechanical response

Possible relationships between the density of peptide innervation and the contractile response of rat cerebral arteries to exogenously applied neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) were examined. The effects of NPY on membrane potential and reactivity of cerebral arteries to exogenous norepinephrine also were studied. In normally innervated arteries there was no apparent correlation between degree of innervation and response to NPY. Marked, prolonged tachyphylaxis to NPY and VIP was observed following brief exposure to these peptides. Surgical removal of the superior cervical ganglia or the sphenopalatine ganglia greatly reduced and, in some cases, eliminated NPY- or VIP-immunoreactive perivascular nerves from cerebral arteries. However, responses of denervated middle cerebral arteries to exogenous NPY or VIP were not different from responses of innervated arteries. Doses of NPY that induced maximal contraction caused no change in membrane potential of the middle cerebral artery. NPY also did not alter the response of cerebral arteries to exogenous norepinephrine. Finally, electrical stimulation of normal or denervated arteries caused only minor constrictor or dilator responses. These results do not support a substantial role for peptidergic perivascular nerves in regulation of pial arterial contractility in the rat.     

Distribution of subgroups of noradrenaline neurons in the coeliac ganglion of the guinea-pig

Summary The distributions within the coeliac ganglion of different chemically coded subgroups of noradrenaline neurons, and the relationships between these neurons and nerve fibres projecting to the ganglion from the intestine, have been assessed quantitatively by use of an immunohistochemical double-staining method. Noradrenaline (NA) neurons made up 99% of all cell bodies. Of these, 21% were also reactive for somatostatin (NA/SOM neurons), 53% were also reactive for NPY (NA/NPY neurons), and 26% were not reactive for either peptide. NA neurons without reactivity for any of the peptides whose localization was tested have been designated NA/-. A small percentage, about 1%, of neurons were reactive for both NPY and SOM. The three major types of NA neurons were arranged in clumps or ribbons throughout the ganglia, with a tendency for NA/SOM neurons to be medial and NA/NPY neurons to be lateral in the ganglia. A small group of neurons (<1%) encoded with dynorphin, NPY and vasoactive intestinal peptide (VIP) was encountered. VIP-immunoreactive nerve terminals, projecting to the ganglion from cell bodies in the intestine, ended around NA/SOM and NA/neurons but not around NA/NPY neurons. Thus, the VIP axons from the intestine end selectively around neurons that modify intestinal function (NA/SOM and NA/-neurons) but not around neurons, the terminals of which supply blood vessels (NA/NPY neurons).     

Localization of substance P,CGRP, VIP,neuropeptide Y,and somatostatin immunoreactive nerve fibers in the carotid labyrinths of some amphibian species

Summary Immunohistochemical localization of substance P (SP), CGRP, VIP, neuropeptide Y (NPY), and somatostatin (SOM) in the carotid labyrinth were compared in some species of amphibians using the peroxidase-antiperoxidase method. Immunoreactivity of SP, CGRP, VIP, and NPY was found in the nerve fibers distributed in the intervascular stroma of the carotid labyrinth. SP, CGRP, and VIP immunoreactive varicose fibers were densely distributed in the peripheral portion of the carotid labyrinth. Some SP-immunoreactive fibers were distributed similarly to CGRP-immunoreactive fibers. The density of NPY and SOM immunoreactive varicose fibers was low. No immunoreactivity of enkephalins was observed in the labyrinth. The intensities of these peptides were varied from species to species. No glomus cells showed immunoreactivity for any of the 7 peptides studied. These results suggest that the vascular regulatory function, which is one of the possible functions of the carotid labyrinth, is controlled by the peptidergic mechanisms in addition to regulation through intimate apposition of glomus and smooth muscle cells (g-s connection).     

Localization of substance P, CGRP, VIP, neuropeptide Y, and somatostatin immunoreactive nerve fibers in the carotid labyrinths of some amphibian species.

Immunohistochemical localization of substance P (SP), CGRP, VIP, neuropeptide Y (NPY), and somatostatin (SOM) in the carotid labyrinth were compared in some species of amphibians using the peroxidase-antiperoxidase method. Immunoreactivity of SP, CGRP, VIP, and NPY was found in the nerve fibers distributed in the intervascular stroma of the carotid labyrinth. SP, CGRP, and VIP immunoreactive varicose fibers were densely distributed in the peripheral portion of the carotid labyrinth. Some SP-immunoreactive fibers were distributed similarly to CGRP-immunoreactive fibers. The density of NPY and SOM immunoreactive varicose fibers was low. No immunoreactivity of enkephalins was observed in the labyrinth. The intensities of these peptides were varied from species to species. No glomus cells showed immunoreactivity for any of the 7 peptides studied. These results suggest that the vascular regulatory function, which is one of the possible functions of the carotid labyrinth, is controlled by the peptidergic mechanisms in addition to regulation through intimate apposition of glomus and smooth muscle cells (g-s connection).     

The effects of pancreatic polypeptides and neuropeptide Y on the rat vas deferens

In order to study the physiological significance of the coexistence of pancreatic polypeptide and norepinephrine (NE) in peripheral noradrenergic nerves, the effects of pancreatic polypeptides of several species were tested on the isolated rat vas deferens. Neuropeptide Y (NPY) was also studied because of its sequence homology to the pancreatic polypeptides. The contractile responses, which were mediated predominantly by activation of noradrenergic nerves following electrical stimulation, were inhibited by bovine pancreatic polypeptide (BPP), human pancreatic polypeptide (HPP), avian pancreatic polypeptide (APP) and NPY in a dose-dependent manner using a constant flow bath. The decreasing order of the inhibitory responses was as follows: BPP = HPP greater than NPY greater than APP. The inhibitory responses produced by BPP and HPP lasted more than 1 hr and displayed a marked tachyphylaxis. In contrast, the inhibitory effects induced by NPY and APP usually returned to the control level after 20-30 min and had minimal tachyphylaxis. The inhibitory action of NPY was still present during alpha-adrenergic blockade. Contractions produced by a single submaximal dose of exogenous NE or serotonin (5-HT) in unstimulated preparations were not affected by pretreatment with NPY. The amplitude of contractions was partially reduced 1 min after pretreatment with BPP or HPP; recovery occurred about 15 min after peptide pretreatment in a constant flow bath. These results suggest that an NPY receptor exists presynaptically in the rat vas deferens and that stimulation of the receptor by NPY inhibits the release of NE from noradrenergic nerves.(ABSTRACT TRUNCATED AT 250 WORDS)     

Staurosporine differentiation of NPFF2 receptor-transfected SH-SY5Y neuroblastoma cells induces selectivity of NPFF activity towards opioid receptors

Activation of the NPFF(2) receptor reduces the inhibitory effect of opioids on the N-type Ca(2+) channel. Although this anti-opioid effect is specific for opioid receptors in neurons and tissues, it also affects NPY Y2 and alpha(2)-adrenoreceptors in undifferentiated SH-SY5Y cells stably expressing the NPFF(2) receptor. To test whether this difference could be due to the immaturity of these cells, they were differentiated to a noradrenergic neuronal phenotype with staurosporine. The differentiated cells ceased to divide and grew long, thin neurites. The inhibition of the depolarization-triggered Ca(2+) transient by activation of G(i)-coupled receptors was either unaffected (micro-opioid), increased (NPY), reduced (NPFF(2)) or lost (alpha(2)-adrenoreceptors). Following a 20 min incubation with 1DMe, the effect of DAMGO was reduced, as in undifferentiated cells, but the effect of NPY was no longer affected. Staurosporine differentiation did not modify the coupling of the micro-opioid and NPFF(2) receptors to the G(i/o) proteins. We suggest that the specificity of the effect of NPFF may not reside in the molecular mechanism of its anti-opioid activity itself but in the organization of receptors within the membrane.     

Dopamine D2 Receptor-Mediated Regulation of Serotonin Extracellular Concentration in the Dorsal Raphe Nucleus of Freely Moving Rats

Abstract: The neuropeptide-inducing activity of neurotrophic factors was tested in cultured cerebral cortical neurons. Brain-derived neurotrophic factor (BDNF) specifically increased contents of the neuropeptides somatostatin (SOM) and neuropeptide Y (NPY), but its effect on contents of cholecystokinin octapeptide and GABA was much less significant. The maximal induction of NPY content (15-fold increase) was achieved by 20 ng/ml of BDNF. These changes were also reproduced at the mRNA level. In contrast, neurotrophin-3 was much less potent at increasing NPY and SOM contents, and nerve growth factor had no effect on them. The expression of mRNA for NPY and SOM was fully dependent on the presence of BDNF in culture but irrelevant to the survival-promoting activity of BDNF, which has been reported previously. Most of the NPY immunoreactivity induced by BDNF was colocalized with glutamate decarboxylase immunoreactivity in cultured cortical neurons. These results suggest that BDNF regulates the peptidergic expression of GABAergic neurons in the cerebral cortex.     

Neuropeptide Y,enkephalin and noradrenaline coexist in sympathetic neurons innervating the bovine spleen

Summary The subcellular distribution of noradrenaline (NA), neuropeptide Y (NPY), Met and Leu-enkephalin (ENK), substance P (SP), somatostatin (SOM), and vasoactive intestinal polypeptide (VIP) was investigated in homogenates of bovine splenic nerve. The distribution of noradrenergic peptide-containing nerves in the bovine celiac ganglion, splenic nerve and terminal areas in spleen was studied by indirect immunofluorescence histochemistry using antisera to tyrosine hydroxylase (TH), dopamine--hydroxylase (DBH), NPY, enkephalin peptides, SP, SOM, VIP and peptide HI (PHI).After density gradient centrifugation, high levels of NPY and ENK-like immunoreactivity (LI) were found in high-density gradient fractions, coinciding with the main NA peak. SP, SOM and VIP were found in fractions with a lower density, VIP being also enriched in a heavy fraction; the latter three peptides were present in low concentrations.Immunohistochemistry revealed that staining for NPYLI and ENK-LI partly overlapped that for TH and DBH in celiac ganglia, splenic nerve axons and terminal areas of spleen. Almost all principal ganglion cells were TH- and DBH-immunoreactive. Many were also NPY-immunoreactive, whereas a smaller number were ENK-positive. In the celiac ganglion patches of dense SP-positive networks and some VIP/PHI- and ENK-immunoreactive fibers were seen around cell bodies.The results indicate that NPY and ENK are stored with NA in large dense-cored vesicles in unmyelinated axons of bovine splenic nerve. SP, SOM and VIP appear in different organelles in axon populations separate from sympathetic noradrenergic nerves.     

Dexfenfluramine treatment and hypothalamic neuropeptides in diet-induced obesity in rats.

Neuropeptide Y (NPY) is a powerful appetite stimulant, and hypothalamic concentrations rise after food deprivation and in experimental diabetes. Serotonergic drugs such as dexfenfluramine are inhibitors of feeding. We measured hyothalamic NPY and NPY mRNA, along with galanin, neurotensin, and somatostatin in chow-fed rats and in rats with dietary obesity, and examined the effect of dexfenfluramine on these peptides in this model. Sixty-five rats were fed a palatable diet (condensed milk, sucrose and chow) for 6 weeks, which produced significant weight gain compared to twenty fed standard chow (145.1 +/- 2.3 g vs. 113.4 +/- 3.2 g, p less than 0.001). Groups of animals were treated for 7 days or 28 days with dexfenfluramine (1.8 mg/kg/day) or saline intraperitoneally via miniosmotic pumps. Hypothalami were dissected into medial and lateral blocks, and NPY, galanin, neurotensin, and somatostatin were measured by radioimmunoassay. Neuropeptide Y mRNA was measured by Northern blotting. Hypothalamic NPY was significantly higher in the palatable diet group compared to chow-fed controls (medial hypothalamus: 86.6 +/- 7.6 vs. 65.7 +/- 4.0 pmol/g tissue, p less than 0.02, lateral hypothalamus 71.2 +/- 6.6 vs. 53.1 +/- 3.6 pmol/g tissue, p less than 0.05), but NPY mRNA was unchanged. Although dexfenfluramine was effective at reducing weight gain in the animals fed the palatable diet, this did not result in any changes in the hypothalamic neuropeptides measured. Neuropeptide Y may be of importance in diet-induced obesity but the weight loss produced by dexfenfluramine in such animals is not mediated by changes in hypothalamic NPY.     

The projections of chemically identified nerve fibres in canine ileum

Summary The projections of nerve fibres with immunoreactivity for the peptides enkephalin (ENK), gastrin-releasing peptide (GRP), neuropeptide Y (NPY), somatostatin (SOM), substance P (SP) and vasoactive intestinal peptide (VIP) were studied in canine small intestine by analysing the consequences of lesions of intrinsic and extrinsic nerves. Of peptides present in fibres supplying myenteric ganglia, GRP, SOM and VIP were in anally directed nerve pathways, whereas ENK and NPY were in orally directed pathways. Pathways ran for up to about 30 mm. SP fibres ran for short distances in both directions in the myenteric plexus. The circular muscle was supplied with ENK, NPY, SP and VIP fibres arising from the myenteric ganglia, whereas most mucosal SP and VIP fibres were deduced to arise from submucous ganglia. There were projections of fibres reactive for ENK, GRP, SOM, SP and VIP from myenteric ganglia to submucous ganglia. Antibodies to tyrosine hydroxylase were used to locate noradrenaline nerve fibres supplying the intestine; these fibres all disappeared when extrinsic nerves running through the mesentery to the small intestine were cut. It is deduced that there is an ordered pattern of projections of peptide-containing fibres in the canine intestine.     

Noradrenergic and peptidergic innervation of the mammary gland in the immature pig

The presence and pattern of coexistence of some biologically active substances in nerve fibres supplying the mammary gland in the immature pig were studied using immunohistochemical methods. The substances studied included: protein gene product 9.5 (PGP), tyrosine hydroxylase (TH), somatostatin (SOM), neuropeptide Y (NPY), galanin (GAL), calcitonin gene-related peptide (CGRP) and substance P (SP). The mammary gland was found to be richly supplied by PGP-immunoreactive (PGP-IR) nerve fibres that surrounded blood vessels, bundles of smooth muscle cells and lactiferous ducts. The vast majority of these nerves also displayed immunoreactivity to TH. Immunoreactivity to SOM was observed in a moderate number of nerve fibres which were associated with smooth muscles of the nipple and blood vessels. Immunoreactivity to NPY occurred in many nerve fibres associated with blood vessels and in single nerves supplying smooth muscle cells. Solitary GAL-IR axons supplied mostly blood vessels. Many CGRP-IR nerve fibres were associated with both blood vessels and smooth muscles. SP-IR nerve fibres richly supplied blood vessels only. The colocalization study revealed that SOM, NPY and GAL partly colocalized with TH in nerve fibres supplying the porcine mammary gland.     

Distribution of neuropeptides in the porcine stellate ganglion

The localization and distribution of neuropeptides including neuropeptide Y (NPY), [Met⁵]enkephalin-Arg⁶-Gly⁷-Leu⁸ (MEAGL), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), substance P and somatostatin (SOM) were analyzed in the stellate ganglion of the pig by use of the indirect immunofluorescence technique. NPY, MEAGL, SOM, VIP and CGRP immunoreactivities were found to exist in subpopulations of neuronal cell bodies of the stellate ganglion. A population of the small intensely fluorescent (SIF) cells showed MEAGL immunoreactivity. In addition, the presence of NPY-, MEAGL-, CGRP-, SP-, SOM- and VIP-immunoreactive nerve fibers and axonal varicosities were observed in the stellate ganglion. The localization and pattern of distribution of these peptides in the porcine stellate ganglion were compared with studies carried out on stellate ganglia of other mammalian species.     

Comparison of the effects of neuropeptide Y (NPY) and 4-norleucine-NPY on isolated perfused rat hearts; effects of NPY on atrial and ventricular strips of rat heart and on rabbit heart mitochondria

Isolated perfused rat hearts were used to compare the effects of the synthetic neuropeptide Y (NPY) and 4-norleucine-NPY on cardiac function. Each peptide exhibited both negative inotropic and chronotropic effects, and also caused coronary vasoconstriction leading to a reduction in coronary flow. A comparison of the IC50 values from dose-response curves using 10(-14) to 10(-7) M peptides (IC50 is the peptide concentration that produced a 50% decrease of the maximal effect) indicated that NPY was more potent as inhibitor of contractility and less potently inhibited coronary flow and heart rate, whereas 4-norleucine-NPY had more inhibitory influence on coronary flow and heart rate and less on cardiac contractility. This difference in potencies suggests that the inhibitory effects of NPY on contractility, coronary flow and heart rate may be independent of each other. Since NPY also decreased the contractile force of isolated left atrial and right ventricular strips of the rat heart, the coronary flow decrease cannot be the cause of the negative inotropy of isolated heart. Pretreatment of atrial and ventricular strips with NPY did not influence the positive inotropic effect produced by the cardiac glycoside ouabain indicating that sarcolemmal Na+, K+-ATPase was not involved in the inhibitory inotropic effect of NPY. Further studies towards elucidating the mechanism of the negative inotropy of cardiac muscles using isolated heart mitochondria revealed that NPY uncoupled oxidative phosphorylation and blocked mitochondrial calcium uptake; the former event fosters negative inotropy. Since these effects on mitochondria occurred at concentrations 100-fold higher than those required for negative inotropy, the two effects of NPY may not be related.     

Neuronal subpopulations in autonomic ganglia associated with the chicken ureter: an immunohistochemical study

The neurochemical coding of neurones located in ganglia of the nerve trunk accompanying the chicken ureter was analysed and quantified using NADPH-diaphorase reactivity and immunohistochemistry against tyrosine hydroxylase (TH), nitric oxide synthase (NOS), calbindin (CAL), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), somatostatin (SOM), substance P (SP) and calcitonin gene-related peptide (CGRP) in untreated or colchicine-treated preparation. Almost all neurones were either positive for TH (38%) or for SOM (60%). Only 4% of the neurones were both TH- and SOM-positive and 3% of the neurones exhibited neither TH nor SOM immunoreactivity. The relative numbers of NPY-, NOS-, CAL- and VIP-positive neurones were 57%, 28%, 14% and 7%, respectively. No SP- or CGRP-positive neurones were observed. All NADPH-diaphorase-positive neurones expressed NOS immunoreactivity. Only in some TH-positive neurones was NPY and/or NOS found. Four major subpopulations were found in the ureteric ganglia. The SOM-positive neurones were subdivided into SOM/NPY/NOS- (28% of all neurones), SOM/NPY- (18%) and SOM/CAL/NPY-positive neurones (14%). A subpopulation of these peptid- ergic neurones also contained VIP. About 35% of the neurones contained TH only. Neurones of all subpopulations (72% of the neurones), except most of the CAL-positive neurones, were encircled by dense plexus of varicose SP/CGRP-positive, presumably sensory nerve fibres. Dense plexus of VIP-positive fibres were observed around 89% of the neurones. The chemical coding of the neuronal subpopulations identified in the ganglia accompanying the chicken ureter resembled that observed in the ganglia of Remak’s nerve but was remarkably different from that of the autonomic neurones described in mammalian species.