Substance P immunoreactivity in the rat adrenal gland during postnatal development.
ABSTRACT Substance P (SP)-immunoreactive nerve fibers in the adrenal medulla was very few during postnatal day 0-5, indicating that its synthesis in the neurons and the transport to nerve endings was incomplete by the end of this period. Since the number of SP-immunoreactive nerve fibers gradually increased during postnatal week 1-2, it was hypothesized that SP was not fully transported to nerve endings until postnatal week 1-2. At postnatal week 3, numerous SP-immunoreactive nerve fibers contacted some noradrenaline (NA) cells but not adrenaline (A) cells in the medulla. From postnatal week 3 onward, the abundance and expression patterns of SP-immunoreactive nerve fibers in the medulla were similar to those in adults. At postnatal week 3, the innervation with SP-immunoreactive nerve fibers was completed indicating the possibility that SP affected on the secretory activity of NA cells but not of A cells in the medulla. The medullary SP-immunoreactive nerve fibers contacting the chromaffin cells possessed a few dense-cored vesicles in their endings at postnatal week 8. Very few SP-immunoreactive chromaffin cells were found in the medulla from postnatal day 0 onward, and SP immunoreactivity was primarily observed in granular cores of the cells suggesting that SP and catecholamine synthesized in the chromaffin cells were released from the granules by adequate stimuli. Very few or a few SP-immunoreactive nerve fibers, acting as a vasomotor effect were found around blood vessels in the superficial cortex from postnatal day 0 onward.
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ABSTRACT: Bovine chromaffin cells were separated by density gradient centrifugation into subfractions enriched with either > 90% adrenaline- or 70-80% noradrenaline-producing cells. Concentrations of epibatidine (an alkaloid with nicotinic receptor activity) as low as 10 nM released adrenaline and noradrenaline from both fractions of cells maintained as monolayer cultures. The maximal effect was evoked by 30 nM epibatidine and was comparable to that evoked by 10 microM nicotine. The catecholamine release from the noradrenaline fraction was 30-40% higher than from the adrenaline fraction. Initial exposure to 50 nM epibatidine reduced release induced by a second exposure to the drug. There was cross-desensitization between epibatidine and nicotine. Substance P inhibited the epibatidine-evoked catecholamine release from both fractions by up to 85% (IC50 = 3-5 microM). The release of noradrenaline was inhibited more than that of adrenaline. In addition, substance P protected the chromaffin cells against desensitization of the nicotinic receptor by epibatidine. The C-terminal heptapeptide sequence of substance P was 10 x less active, two N-terminal sequences did not modulate the catecholamine release.European Journal of Pharmacology 07/1997; 328(2-3):249-54. · 2.59 Impact Factor
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ABSTRACT: The recent availability of antisera to the vesicular acetylcholine transporter (VAChT) and choline acetyltransferase (ChAT) that demonstrate peripheral cholinergic neurons has made possible the anatomical identification of cholinergic neurons in the enteric nervous system. In this study, we localised cholinergic neurons in the mouse small and large intestine and identified which substances are found colocalised in the cholinergic neurons. Immunohistochemical single and double staining techniques were used on whole mount preparations and frozen sections to examine the localisation and chemical coding of cholinergic neurons in the small and large intestine of the mouse. Cholinergic neurons were identified using antisera to ChAT or VAChT. In both the small and large intestine, numerous ChAT-immunoreactive nerve cell bodies were present in the myenteric and submucous ganglia, and ChAT- and VAChT-immunoreactive nerve terminals were abundant in the myenteric and submucous plexuses and the external muscle. Previous studies have identified two major classes of myenteric neurons in the small intestine of the mouse--those containing calretinin plus substance P, and those containing nitric oxide synthase (NOS) plus vasoactive intestinal peptide (VIP). Double-label studies showed that the vast majority of the calretinin/substance P neurons were cholinergic neurons, whereas only a small proportion of the NOS/VIP cells were cholinergic; the noncholinergic NOS/VIP neurons were motor neurons or interneurons, whereas the cholinergic NOS/VIP neurons appeared to be exclusively interneurons. In the small intestine, all of the 5-HT-loaded neurons and a subpopulation of the calbindin neurons were also cholinergic. In the large intestine, there was a pattern of overlaps similar to that found in the small intestine, except that in the large intestine approximately 25% of the calretinin cells were not cholinergic. Only approximately one third of the GABA-loaded neurons in the large intestine were cholinergic. Large subpopulations of motor neurons and interneurons in the mouse small intestine are cholinergic neurons.The Anatomical Record 07/1998; 251(2):185-99.
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ABSTRACT: Met-enkephalin-like immunoreactivity has been observed in adrenal medullary gland cells of the rat, guinea-pig and cat. There were marked quantitative differences in untreated animals. Most medullary gland cells were positive in the cat, a large proportion in the guinea-pig but only a few in the rat. After sectioning of the splanchnic nerve, however, a large proportion of the gland cells were met-enkephalin positive also in the rat. Occasionally the met-enkephalin-like immunoreactivity had a granular appearance suggesting that the storage sites could be vesicular.In the guinea-pig a moderate number of met-enkephalin immunoreactive nerve fibers were observed in the adrenal medulla. They disappeared to a large extent after sectioning of the splanchnic nerve. A few fibers were also seen in the rat adrenal medulla, and in the cat some fibers could be seen in areas with few immunoreactive cells.The present findings suggest that in the adrenal medulla an enkephalin-like peptide(s) is present both in gland cells and in nerve terminals arising mainly from fibers in the splanchnic nerve. Thus, the possibility exists that in the adrenal medulla opioid peptides may be released from the gland cells into the blood as hormones as well as from nerve terminals to act as a modulator or transmitter. It should, however, be emphasized that the well-documented metabolic instability of met-enkephalin may be somewhat difficult to reconcile with a hormonal role of this peptide.Neuroscience 02/1978; 3(12):1169-86. · 3.12 Impact Factor