Search results for "Myenteric Plexus"
showing 10 items of 46 documents
Benzimidazolones and renzapride facilitate acetylcholine release from guinea-pig myenteric plexus via 5-HT4 receptors
1995
The effects of the 5-HT4 receptor agonists BIMU 8, BIMU 1, renzapride and of the 5-HT1p receptor agonist 5-hydroxyindalpine on basal and electrically evoked outflow of tritium were studied in guinea-pig longitudinal muscle myenteric plexus preparations preincubated with [3H]choline. Muscle contractions were recorded simultaneously. BIMU 8 caused a calcium dependent and tetrodotoxin sensitive increase in basal [3H]outflow that was assumed to represent release of [3H]acetylcholine. In addition, BIMU 8 enhanced the release of [3H]acetylcholine and twitch contractions evoked by submaximal electrical stimulation. Ondansetron (1 μmol/l) did not change the effects of BIMU 8, but DAU 6285 and tropi…
Increase by 5-hydroxykynuramine of spontaneous acetylcholine release from myenteric neurons: mediated by serotonin M receptors
1987
The effects of 5-hydroxykynuramine (5-OH-K) and of 3-(2-amino-5-hydroxyphenyl)-propaneamine (AHPP) on spontaneous and electrically evoked release of [3H]acetylcholine were studied in the guinea-pig myenteric plexus longitudinal muscle preparation preincubated with [3H]choline. 5-OH-K caused a concentration-dependent increase in spontaneous [3H]acetylcholine release (EC50 5.3 microM). This effect was diminished in the presence of a desensitizing concentration of 5-hydroxytryptamine (5-HT). AHPP (1-100 microM) did not affect the spontaneous outflow of [3H]acetylcholine. The electrically evoked release of [3H]acetylcholine was significantly reduced in the presence of 100 microM of either 5-OH-…
Spasmolytic Effects of Aphanizomenon Flos Aquae (AFA) Extract on the Human Colon Contractility.
2021
The blue-green algae Aphanizomenon flos aquae (AFA), rich in beneficial nutrients, exerts various beneficial effects, acting in different organs including the gut. Klamin® is an AFA extract particularly rich in β-PEA, a trace-amine considered a neuromodulator in the central nervous system. To date, it is not clear if β-PEA exerts a role in the enteric nervous system. The aims of the present study were to investigate the effects induced by Klamin® on the human distal colon mechanical activity, to analyze the mechanism of action, and to verify a β-PEA involvement. The organ bath technique, RT-PCR, and immunohistochemistry (IHC) were used. Klamin® reduced, in a concentration-dependent manner, …
Effects of K(ATP) channel modulators on acetylcholine release from guinea-pig isolated atria and small intestine.
2002
The effects of K(ATP) channel blockers (glibenclamide, HMR 1883, HMR 1372) and openers (cromakalim, pinacidil, diazoxide) on the electrically-evoked (5 Hz) release of [(3)H]acetylcholine were studied in isolated guinea-pig atria and myenteric plexus-longitudinal muscle preparations which had been preincubated with [(3)H]choline. Atria: Cromakalim (0.3 microM and 1 microM), pinacidil (10 microM) and diazoxide (30 microM) significantly reduced the stimulation-evoked release of [(3)H]acetylcholine. The inhibition produced by cromakalim and pinacidil was prevented by 1 microM of either HMR 1883, HMR 1372 or glibenclamide. The blockers alone significantly increased the release at concentrations …
Effects of cromakalim on acetylcholine release and smooth muscle contraction in guinea-pig small intestine
1989
The effects of the potassium channel opener cromakalim on smooth muscle contraction and 3H-acetyl-choline release were studied simultaneously in guinea-pig longitudinal muscle myenteric plexus preparations which had been preincubated with 3H-choline. Cromakalim (10 mumol/l) inhibited more markedly the smooth muscle contractions caused by the release of endogenous acetylcholine (via electrical stimulation or via activation of nicotine- and 5-HT3-receptors) than contractions induced by pilocarpine. Cromakalim (10 mumol/l) did not affect the release of 3H-acetylcholine evoked by electrical stimulation or by stimulation of nicotine- and 5-HT3-receptors. In contrast, the release of 3H-acetylchol…
Isolation of Cholinergic Synaptic Vesicles from the Myenteric Plexus of Guinea-Pig Small Intestine
1980
The acetylcholine-rich myenteric plexus-longitudinal muscle preparation of the guinea-pig small intestine has been subjected to subcellular fractionation using modifications of both classical methods and that originally devised for bulk isolation of cholinergic synaptic vesicles from the electromotor nerve terminals of Torpedo marmorata by means of density gradient centrifugation in a zonal rotor. The latter method gave a vesicle fraction with the highest acetylcholine content so far recorded for a mammalian particulate fraction, 30.9 +/- S.E.M. 1.8 (5) nmol of acetylcholine . mg of protein-1. Electron-microscopical examination showed that it consisted of a homogeneous preparation of vesicl…
Spontaneous release of endogenous 5-hydroxytryptamine and 5-hydroxyindoleacetic acid from the isolated vascularly perfused ileum of the guinea-pig
1987
The spontaneous release of 5-hydroxytryptamine and its metabolite 5-hydroxyindoleacetic acid from the enterochromaffin cells of the small intestine into the portal circulation was investigated in vitro using the vascularly perfused ileum of the guinea-pig. The release of 5-hydroxytryptamine decreased by 70% in a calcium-free medium and by 35% in the presence of tetrodotoxin. Inhibition of monoamine oxidase activity by pargyline (100 microM) had no effect on the spontaneous release of 5-hydroxytryptamine although it caused a 75% reduction in the outflow of 5-hydroxyindoleacetic acid. Imipramine (1 microM), an inhibitor of neuronal uptake of 5-hydroxytryptamine, reduced the 5-hydroxyindoleace…
Gastric α-synuclein immunoreactive inclusions in Meissner's and Auerbach's plexuses in cases staged for Parkinson's disease-related brain pathology
2005
The progressive degenerative process associated with sporadic Parkinson's disease (sPD) is characterized by formation of alpha-synuclein-containing inclusion bodies in a few types of projection neurons in both the enteric and central nervous systems (ENS and CNS). In the brain, the process apparently begins in the brainstem (dorsal motor nucleus of the vagal nerve) and advances through susceptible regions of the basal mid-and forebrain until it reaches the cerebral cortex. Anatomically, all of the vulnerable brain regions are closely interconnected. Whether the pathological process begins in the brain or elsewhere in the nervous system, however, is still unknown. We therefore used immunocyt…
Connexin36 (Cx36) expression and protein detection in the mouse carotid body and myenteric plexus
2013
AbstractAlthough connexin36 (Cx36) has been studied in several tissues, it is notable that no data are available on Cx36 expression in the carotid body and the intestine. The present study was undertaken to evaluate using immunohistochemistry, PCR and Western blotting procedures, whether Cx36 was expressed in the mouse carotid body and in the intestine at ileum and colon level. In the carotid body, Cx36 was detected as diffuse punctate immunostaining and as protein by Western blotting and mRNA by RT-PCR. Cx36 punctate immunostaining was also evident in the intestine with localization restricted to the myenteric plexus of both the ileum and the colon, and this detection was also confirmed by…
Effects of 5-HT4 receptor stimulation on basal and electrically evoked release of acetylcholine from guinea-pig myenteric plexus
1992
The effects of 5-methoxytryptamine and 5-hydroxytryptamine (5-HT) on both basal and electrically evoked outflow of tritium were studied in guinea-pig myenteric plexus preparations preincubated with [3H]-choline. Basal outflow. 5-Methoxytryptamine caused a transient and calcium-dependent increase in basal outflow of [3H]acetylcholine that was abolished by tetrodotoxin. Ondansetron (1 μmol/1) did not affect the stimulatory response of 5-methoxytryptamine but ICS 205-930 (1 and 3 μmol/1) produced parallel rightward displacements of the concentration-response curve to 5-methoxytryptamine. The PKB value for ICS 205-930 was 6.6 suggesting an involvement of 5-HT4 receptors. 5-HT caused an increase…