Search results for "Myenteric plexus"

Altered gastrointestinal motility in an animal model of Lesch-Nyhan disease.

2018

Mutations in the HGPRT1 gene, which encodes hypoxanthine-guanine phosphoribosyltransferase (HGprt), housekeeping enzyme responsible for recycling purines, lead to Lesch-Nyhan disease (LND). Clinical expression of LND indicates that HGprt deficiency has adverse effects on gastrointestinal motility. Therefore, we aimed to evaluate intestinal motility in HGprt knockout mice (HGprt(−)). Spontaneous and neurally evoked mechanical activity was recorded in vitro as changes in isometric tension in circular muscle strips of distal colon. HGprt(−) tissues showed a lower in amplitude spontaneous activity and atropine-sensitivity neural contraction compared to control mice. The responses to carbachol a…

Modulation by Scopolamine, Acetylcholine and Choline of the Evoked Release of Acetylcholine from the Guinea Pig Myenteric Plexus: Evidence for a Musc…

1981

There is evidence that the release of acetylcholine (ACh) from the guinea pig myenteric plexus is controlled via presynaptic muscarine receptors. Muscarinic antagonists such as atropine enhance the release evoked by either electrical field stimulation, by nicotinic drugs or by high K+ concentrations (4,7,10). On the other hand, the muscarinic agonist oxotremorine inhibits the evoked release of ACh (7). A comparable feedback inhibition has been described for the release of ACh from central cholinergic nerves (for review, see Ref. 12). However, it has so far not been shown whether the physiological transmitter itself is able to depress the release of neuronal ACh. We have, therefore, studied …

Exogenous glucagon-like peptide-1 reduces contractions in human colon circular muscle.

2014

Glucagon-like peptide 1 (GLP1) is a naturally occurring peptide secreted by intestinal L-cells. Though its primary function is to serve as an incretin, GLP1 reduces gastrointestinal motility. However, only a handful of animal studies have specifically evaluated the influence of GLP1 on colonic motility. Consequently, the aims of this study were to investigate the effects induced by exogenous GLP1, to analyze the mechanism of action, and to verify the presence of GLP1 receptors (GLP1Rs) in human colon circular muscular strips. Organ bath technique, RT-PCR, western blotting, and immunofluorescence were used. In human colon, exogenous GLP1 reduced, in a concentration-dependent manner, the ampl…

Modulation by oxotremorine and atropine of acetylcholine release evoked by electrical stimulation of the myenteric plexus of the guinea-pig ileum

1977

1. The effects of oxotremorine and atropine on the release of acetylcholine from longitudinal muscle strips of the guinea-pig ileum stimulated at frequencies between 0.1 and 3 Hz in the presence of eserine were investigated. In control experiments the acetylcholine output per stimulus declined with increasing frequencies of stimulation. 2. Oxotremorine inhibited the release of acetylcholine in a concentration-dependent fashion. At a concentration of 10−6 M oxotremorine, the release evoked by 0.1 Hz was reduced by 54%. With increasing frequencies of stimulation the inhibitory effect of oxotremorine became smaller. 3. Atropine enhanced the output of acetylcholine evoked by electrical stimulat…

Muscarinic Modulation of Acetylcholine Release from the Myenteric Plexus of the Guinea Pig Small Intestine

1978

The concept of a local feedback regulation of neurotransmitter release has been most intensively studied in the adrenergic system (See Ref. 13 for review). The feedback hypothesis of noradrenaline release is based on the findings that α-adrenolytic drugs enhance, and α-adrenoceptor agonists reduce neuronal noradrenaline release. Relatively few systematic studies have been made on the influence of cholinolytic and cholinomimetic drugs on the release of ACh. Szerb and Somogyi (14) reported that the potent muscarinic agonist oxotremorine inhibited ACh output from cerebral cortical slices. Further, the muscarinic antagonists atropine and hyoscine have been found to facilitate the release of ACh…

Nitrergic modulation of gastrointestinal function during early endotoxemia.

2006

After bacterial infection, the host reacts by signalling to the central nervous system where a cascade of physiologic, neuroendocrine and behavioural processes is orchestrated, collectively termed the acute phase response. Endotoxemia following Gram-negative bacterial infection induces a wide array of effects, including fever, loss of appetite and changes in gastrointestinal function that attempt to eliminate the challenge and restore homeostasis. Systemic administration of low doses of endotoxin (5-40 microg/kg) to rats is associated with changes in gastrointestinal motor function, inhibition of gastric acid secretion and increase in the gastric mucosal resistance to damage. These changes …

Heteroreceptor-mediated modulation of noradrenaline and acetylcholine release from peripheral nerves

2006

In Vivo Imaging of Enteric Neuronal Networks in Humans Using Confocal Laser Endomicroscopy

2012

Plasticity of mouse enteric synapses mediated through endocannabinoid and purinergic signaling

2012

The myenteric and submucosal plexuses of the enteric nervous system (ENS) exist as interconnected integrative nerve networks within the wall of the gastrointestinal (GI) tract. Activity of the ENS is responsible for the control of the digestive and protective functions of the gut.1 Synaptic transmission between enteric neurons propagates information from intrinsic afferent neurons to interneurons, and then from interneurons to motor neurons that control final effectors such as smooth muscle and the secretory epithelium. Acetylcholine (ACh) is the major excitatory neurotransmitter in the myenteric plexus, acting on nicotinic receptors at synapses between neurons and on muscarinic receptors a…

Achalasie im Kindesalter: Eine separate Entität?

2007

Background Achalasia in childhood is rare, also the etiology and the pathogenesis of the early onset ort he disease is practically unknown. Little is known about the neuropathological changes in structure of the esophageal wall in non-hereditary, sporadic achalasia in children and ist differentiation to that in adults. The aim of our study was to examine the morphological properties or high-pressure zone of the lower esophageal sphincter in children who had undergone a Heller myotomy because of achalasia as well as to compare them with the pathological findings in adults. Methods Muscle biopsies of the smooth musculature, a 20 x 10 mm long segment of the myenteric of the distal esophagus (l…