Origin of peptide-containing fibers in the inferior mesenteric ganglion of the guinea-pig: immunohistochemical studies with antisera to substance P, enkephalin, vasoactive intestinal polypeptide, cholecystokinin and bombesin

Dynorphin-immunoreactive neurons in the autonomic nervous system

The distribution of dynorphin-like immunoreactivity in the autonomic nervous system of the rat and guinea-pig was investigated using an antiserum raised against dynorphin-(1-17). Dynorphin-like immunoreactivity was observed in fiber networks in the prevertebral sympathetic ganglia, in fibers in the enteric plexa , circular muscle layer and a few in the lamina muscularis of the mucosa of the gastrointestinal tract. After colchicine treatment dynorphin-immunoreactive cell bodies were observed both in the myenteric and submucous ganglia of the gut. The paravertebral ganglia contained occasional dynorphin-positive fibers and a few immunoreactive small intensely fluorescent cells. The distribution of the dynorphin-like immunoreactivity was compared to the distribution of enkephalin-like immunoreactivity, and it was found that in some areas there were similarities in the distribution patterns, although in other areas there were clear differences, indicating a non-identity of these two systems.

The molecular nature of cholecystokinin in the feline pancreas and related nervous structures

Nerve terminals in pancreatic islets and ganglia containing cholecystokinin (CCK)/gastrin-like peptides are particularly abundant in the cat. In order to elucidate the possible origin and molecular nature of the peptides in these nerves, extracts of the feline pancreas, vagus, sympathetic trunk, and celiac-superior mesenteric ganglion were examined by gel chromatography monitored by sequence-specific radioimmunoassays. Small amounts of CCK-33 and CCK-8 were present in the pancreatic terminals. In the vagus and the sympathetic trunk, CCK, mainly as CCK-8, occurred in concentrations of 3.5 and 3.7 pmol/g. The celiac-superior mesenteric ganglion contained 40 pmol CCK/g distributed in five forms, including a predominant CCK-8-like component and a component eluting like CCK-4. Gastrins were not detected in the nervous structures. The results suggest that the celiac-superior mesenteric ganglia, the vagal nerves and the sympathetic trunks all may contribute to the CCK nerve terminals in the feline pancreas.

Distribution and projections of neurons with immunoreactivity for both gastrin-releasing peptide and bombesin in the guinea-pig small intestine

Bombesin-like and gastrin-releasing peptide (GRP)-like immunoreactivities were localized in nerves of the guinea-pig small intestine and celiac ganglion with the use of antibodies raised against the synthetic peptides. The anti-bombesin serum (preincubated to avoid cross reactivity with substance P) and the anti-GRP serum revealed the same population of neurons. Preincubation of the anti-bombesin serum with bombesin abolished the immunoreactivity in nerves while absorption of the anti-GRP serum with either bombesin or the 14-27 C-terminal of GRP only reduced the immunoreactivity. The immunoreactivity was abolished by incubation with GRP 1-27. Immunoreactive nerves were found in the myenteric plexus, circular muscle, submucous plexus and in the celiac ganglion. Faintly reactive nerve cell bodies were found in the myenteric ganglia (3.2% of all neurons) but not in submucous ganglia. After all ascending and descending pathways in the myenteric plexus had been cut, reactive terminals disappeared in the myenteric plexus, circular muscle (including the deep muscular plexus) and the submucous plexus on the anal side. After the mesenteric nerves were cut no changes were observed in the intestinal wall but the reactive fibres in celiac ganglia disappeared. It is deduced that GRP/bombesin-immunoreactive nerve cell bodies in myenteric ganglia project from the myenteric plexus to other myenteric ganglia situated further anally (average length 12 mm), anally to the circular muscle (average length 9 mm), anally to submucous ganglia (average length 13 mm) and external to the intestine to the celiac ganglia.(ABSTRACT TRUNCATED AT 250 WORDS)

Separate origins for the dynorphin and enkephalin immunoreactive fibers in the inferior mesenteric ganglion of the guinea pig

By different denervation procedures the origin of dynorphin-(1-17) and enkephalin immunoreactive fibers in the guinea pig inferior mesenteric ganglion was investigated. It was found that the dynorphin-(1-17)-positive fibers reached the ganglion predominantly via the colonic nerves and to a lesser extent via the hypogastric and intermesenteric nerves whereas the enkephalin-positive fibers reached the ganglion via the lumbar splanchnic nerves. These findings show that the dynorphin-(1-17) and enkephalin systems are separate in this ganglion.

Co-localization of cyclic GMP in superior cervical ganglion with peptide neurotransmitters

The immunofluorescent localization of cyclic 3',5'-guanosine monophosphate (cyclic GMP) in rat superior cervical ganglion has been compared to postganglionic neurons having immunoreactivity to neuropeptides. Cyclic GMP-positive somata are equally distributed among cell bodies fluorescent for substance P, somatostatin, and methionine-enkephalin. 40% of the total number of cells stained for each peptide demonstrate co-incident cyclic GMP localization, suggesting a large majority of the neurons employ non-cyclic GMP mechanisms.

Capsaicin-induced depletion of substance P-like immunoreactivity in guinea pig sympathetic ganglia

The distribution of substance P immunoreactive nerve fibers in guinea pig sympathetic ganglia was studied in normal and capsaicin-treated animals. A marked depletion of substance P-like immunoreactivity was observed in both pre- and paravertebral ganglia after capsaicin treatment. In the inferior mesenteric and pelvic ganglia, however, intensely fluorescent fibers surrounding some of the principal ganglion cells remain after capsaicin treatment. Ligation experiments on the inferior mesenteric ganglion indicate that the capsaicin-insensitive substance P immunoreactive fibers in this ganglion are of lumbar splanchnic origin. Whether or not they represent capsaicin-resistant primary afferent neurons is not known. The enkephalin, vasoactive intestinal polypeptide, cholecystokinin and bombesin immunoreactive fiber networks in the inferior mesenteric ganglion were also studied, and no differences were observed between normal and capsaicin-treated animals.

Immunohistochemical indications of gastrin releasing peptide--bombesin-like immunoreactivity in the nervous system of the rat. Codistribution with substance P-like immunoreactive nerve terminal systems and coexistence with substance P-like immunoreactivity in dorsal root ganglion cell bodies

Weak to strong gastrin releasing peptide--bombesin (GRP-Bn)-like immunoreactivity was found in fine varicose nerve terminal systems of low to high densities in several parts of the CNS. The highest densities of strongly immunoreactive terminals were found in the marginal layer and in the substantia gelatinosa of the spinal cord, and in parts of the nuc. tractus spinalis nervi trigemini. Morphometrical analysis in the spinal cord demonstrates that GRP-BN-like-immunoreactive and substance P (SP), but not somatostatin (SS)-immunoreactive nerve terminals strikingly codistribute. Coexistence of SP and GRP-BN-like immunoreactivities was demonstrated in trigeminal and spinal ganglion nerve cells. Thus, GRP-BN-like immunoreactivity may coexist with SP in certain SP-immunoreactive nerve terminal systems.

Bombesin-like immunoreactivity in sympathetic ganglia

Nerve fibres showing immunoreactivity for bombesin have been observed in prevertebral sympathetic ganglia of the rat and guinea-pig. The distribution of bombesin immunoreactive fibres was compared with the distribution of the structurally-related peptide substance P. Dense networks of varicose bombesin immunoreactive fibres were observed, and in the rat coeliac ganglion the density exceeded that of the substance P immunoreactive fibres. Extracts of rat and guinea-pig coeliac ganglion contained material cross-reacting in radioimmunoassays for bombesin tetradecapeptide. Similar concentrations of bombesin and substance P were found in the guinea-pig ganglion, whereas in the rat the concentration of bombesin was about 20 times as high as that of substance P. Two molecular forms of immunoreactive bombesin were identified, neither of which corresponded exactly to synthetic bombesin. The two components were also distinguishable from synthetic substance P. A potential role of a bombesin-like peptide in neural pathways between the gut and prevertebral ganglia is suggested.