Search results for "Myenteric plexus"
showing 6 items of 46 documents
Effects of nicotine receptor agonists on acetylcholine release from the isolated motor nerve, small intestine and trachea of rats and guinea-pigs
1992
The effects of nicotine receptor agonists on the release of [3H]acetylcholine from the phrenic nerve, the small intestine and the trachea were investigated to characterize neuronal nicotine receptors within the peripheral nervous system. Contraction of the indirectly-stimulated hemidiaphragm was recorded to investigate desensitization of the postsynaptic muscular nicotine receptors. Nicotine, cytisine, 1,1-dimethyl-4-phenylpiperazinium and 2-(4-aminophenyl)-ethyl-trimethyl-ammoniumiodide caused a concentration-dependent (0.1-30 microM) increase in evoked [3H]acetylcholine release from the phrenic nerve, whereby bell-shaped concentration-response curves were obtained. The rank order of decre…
Increase by NO synthase inhibitors of acetylcholine release from guinea-pig myenteric plexus
1994
The effects of nitric oxide (NO) synthase inhibitors on the electrically evoked release of [3H]acetylcholine were studied in guinea-pig myenteric plexus preparations preincubated with [3H]choline. NG-monomethyl-L-arginine (EC50 5.3 mumol l-1) and NG-nitro-L-arginine (EC50 1.3 mumol l-1) concentration-dependently increased the evoked release of [3H]acetylcholine without affecting the basal outflow. The facilitatory effect of NG-mono-methyl-L-arginine was prevented by L-arginine but not by D-arginine. The results suggest that endogenous NO inhibits the depolarisation-evoked release of acetylcholine.
Choline inhibits acetylcholine release via presynaptic muscarine receptors
1981
The effect of exogenous choline on the outflow of 3H-acetylcholine evoked by field stimulation was studied on the myenteric plexus-longitudinal muscle preparation of the guinea pig. Choline at concentrations of 100 microM and higher depressed the evoked outflow of 3H-acetylcholine in a concentration-dependent manner. The EC50 for the inhibitory action was 300 microM. Scopolamine (10 nM) antagonized the effect of choline which indicates that the inhibition of 3H-acetylcholine outflow is mediated by muscarine receptors. The findings imply that choline at high concentrations does not improve cholinergic synaptic neurotransmission in tissues that are endowed with presynaptic muscarine receptors…
Two types of neuronal muscarine receptors modulating acetylcholine release from guinea-pig myenteric plexus
1985
Longitudinal muscle strips of the guinea-pig ileum were incubated with [3H]choline and the effects of muscarinic agonists on smooth muscle contraction and on spontaneous and electrically-evoked outflow of tritium were studied. Muscarine and pilocarpine concentration-dependently increased both muscle contraction and spontaneous outflow of [3H]ACh, and inhibited the electrically-evoked outflow of [3H]ACh. The increase in spontaneous outflow was prevented by tetrodotoxin and scopolamine, but not by hexamethonium. Oxotremorine (1-100 microM) did not increase the spontaneous outflow of tritium. Pirenzepine in concentrations of 10 and 100 nM hardly affected the muscle contractions induced by pilo…
The clinical relevance of non-classified dysganglionoses and implications for a new grading system
2001
In addition to the classified types of dysganglionosis, certain non-classified dysganglionoses (NCD) (types 1-4) were introduced by Meier-Ruge in 1992. Clinical data on these conditions are limited. Among 134 children with intestinal dysganglionoses (ID) treated from 1979 to 1999, 12 were identified to have a NCD. Their clinical course is presented. The existence of mild ID (type 1) is difficult to demonstrate. Current definitions and data on clinical relevance are not convincing. An indication for surgical treatment is not present. Isolated hypogenesis of the submucous plexus (SMP) (type 2, n = 8) is clinically a more severe kind of intestinal neuronal dysplasia type B and often requires e…
Ösophagusresektion bei unspezifischer Motilitätsstörung der Speiseröhre - Bedeutung der neuropathologischen Befunde
2005
A 47-year-old patient presented with a history of dysphagia for solid food for almost 10 years and weight loss of more than 50 kg. Non-resecting surgical as well as endoscopic procedures (laparoscopic cardiomyotomy with secondary antireflux operations, balloon dilation, Botulinum-toxin injection) were without success. A barium esophagogram showed a confinement of the distal esophagus with a filiform passage of the contrast medium and undigested food in the prestenotic dilated esophageal corpus. Manometry displayed a hypertensive lower esophageal sphincter with a resting pressure of 43.8 mmHg - although completely relaxing. The tubular esophagus was aperistaltic with 100 % simultaneous and r…