Search results for "acetylcholine receptor"
showing 10 items of 263 documents
Cholinergic modulation of the release of 5-hydroxytryptamine from the guinea pig ileum.
1987
Isolated segments of the guinea pig ileum were vascularly perfused and the release of 5-HT and its metabolite 5-HIAA into the portal venous effluent determined by HPLC with electrochemical detection. Test substances were applied via the arterial perfusion medium. Oxotremorine inhibited concentration-dependently the release of 5-HT and 5-HIAA (by 47% at 1 mumol/l). Scopolamine (0.1 mumol/l) did not affect the release of 5-HT and 5-HIAA, but antagonized the effect of oxotremorine. In the presence of TTX (1 mumol/l), oxotremorine (1 mumol/l) increased the release of 5-HT by 150% and that of 5-HIAA by 220%. This increase was completely blocked by scopolamine. Hexamethonium (100 mumol/l) and TTX…
Characterization of the muscarine receptors involved in the modulation of serotonin release from the vascularly perfused small intestine of guinea pi…
1989
Isolated small intestinal segments of the guinea pig were arterially perfused and the release of 5-hydroxytryptamine (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) into the portal venous effluent measured by HPLC with electrochemical detection. Test substances were applied via the arterial perfusion medium. McN-A-343, pilocarpine and oxotremorine inhibited concentration-dependently the outflow of 5-HT and 5-HIAA. Pirenzepine (0.03-0.1 mumol/l) which can discriminate between M1 and M2-receptor subtypes antagonized completely this inhibitory effect. In the presence of 1 mumol/l tetrodotoxin (TTx), all three muscarine receptor agonists increased the outflow of 5-HT and 5-HIAA. O…
Expression of nicotinic acetylcholine receptors in the rat superior cervical ganglion on mRNA and protein level.
1994
The expression of nicotinic acetylcholine receptors (nAChR) in the rat superior cervical ganglion was investigated by Western blotting, immunohistochemistry and non-radioactive in situ hybridization applying probes for the alpha 4-1 and beta 2 subunit mRNA. Immunoblot analysis of homogenized ganglia using the anti-nAChRs antibody WF6 revealed a labeled protein band of apparent molecular weight of 40 kDa which is typical for the alpha subunit of nAChRs. Applying double-labeling immunofluorescence with antibodies against tyrosine hydroxylase, nAChR-like molecules were identified in most postganglionic neurons and in a subpopulation of small intensely fluorescent (SIF) cells. alpha 4-1 and bet…
The effects of methacholine and calcium deprivation on the release of the false transmitter, ?-methyladrenaline, from the isolated rabbit heart
1976
1. Anaesthetized rabbits were infused for 20 min with 85 μg · kg−1 · min−1 (±)-α-methyladrenaline. The hearts dissected 15 min after the infusion contained 1.49 μg/g α-methyladrenaline; the endogenous noradrenaline content was correspondingly decreased. 2. Hearts from α-methyladrenaline-infused animals were isolated with the right sympathetic nerves intact and perfused. Ventricular rate, right atrial and right ventricular tensions were recorded using the transverse method. 3. Electrical stimulation (10 Hz, 1 ms, 1 min) of sympathetic nerves, perfusion with the nicotinic drug, p-aminophenethyltrimethylammonium (PAPETA) or perfusion with 54 mM KCl (high K+) solution evoked an output of both α…
The effect of methacholine on noradrenaline release from the rabbit heart perfused with indometacin
1974
The experiments were undertaken in order to study the effect of inhibition of prostaglandin synthesis on the muscarinic inhibition of noradrenaline release evoked by sympathetic nerve stimulation. The right sympathetic nerves of the perfused rabbit heart were stimulated electrically. The noradrenaline output was enhanced after perfusion of the hearts with indometacin 3×10−5 M indicating blockade of the prostaglandin-mediated negative feedback control. Both in the presence and in the absence of indometacin methacholine 4×10−5 M decreased the noradrenaline output by a similar percentage. It is concluded that the muscarinic inhibition of noradrenaline release does not require the functional in…
AF-DX 116 differentiates between prejunctional muscarine receptors located on noradrenergic and cholinergic nerves.
1989
Prejunctional affinity constants of the cardioselective muscarine receptor antagonist AF-DX 116 (11-[(2-[(diethyl-amino)methyl]-1-piperidinyl)acetyl]-5,11-dihydro-6 H-pyrido [2,3-b] [1,4] benzodiazepine-6-one) were determined for muscarine autoreceptors on cholinergic nerves of the guinea-pig ileum and for heteroreceptors on noradrenergic nerves of the rat heart and guinea-pig iris. AF-DX 116 antagonized with low affinity the muscarinic inhibition induced by arecaidine propargyl ester of the stimulation-evoked [3H]acetylcholine overflow (pA2 6.74) from the guinea-pig ileum. In contrast, AF-DX 116 was more potent in antagonizing the methacholine-induced inhibition of the stimulation-evoked […
Expression of the α4 isoform of the nicotinic acetylcholine receptor in the fetal human cerebral cortex
2001
Nicotinic acetylcholine receptors are likely to play an important role in neuronal migration during development. Furthermore, the alpha4 receptor subunit gene is related to a hereditary juvenile form of epilepsy. Only little information is available, however, on the expression of cerebrocortical nicotinic acetylcholine receptors during human fetal development. Using non-isotopic in situ hybridization and immunohistochemistry, we have studied the distribution of the alpha4 subunit of the nicotinic acetylcholine receptor mRNA and protein in the human frontal cortex at middle (17-24 weeks of gestation) and late (34-42 weeks of gestation) fetal stages. Both, alpha4 receptor mRNA and alpha4 rece…
A presynaptic excitatory M1 muscarine receptor at postganglionic cardiac noradrenergic nerve fibres that is activated by endogenous acetylcholine.
1990
Rabbit atria were isolated with the extrinsic right vagus and sympathetic nerves intact and perfused with Tyrode solution. Noradrenaline overflow evoked by sympathetic nerve stimulation (SNS) at 3 Hz for 3 min was determined before, during, and after vagus nerve stimulation (VNS), also at 3 Hz and for 3 min. The VNS pulses preceded the SNS pulses by 3, 100 and 233 ms. Acetylcholine overflow was determined after labelling of the transmitter stores with [14C]choline. Pirenzepine 80 nmol/l failed to alter the muscarinic inhibition of noradrenaline overflow when the vago-sympathetic impulse intervals were 3 and 233 ms. At an interval of 100 ms VNS did not significantly inhibit noradrenaline ove…
Nicotine enhances antisaccade performance in schizophrenia patients and healthy controls
2013
Abstract Nicotine has been proposed to be a cognitive enhancer, particularly in schizophrenia patients. So far, the published studies of nicotine effects on antisaccade performance in schizophrenia patients only tested participants who were deprived smokers. Thus, we aimed to test both smoking and non-smoking patients as well as healthy controls in order to extend previous findings. Moreover, we employed a paradigm using standard and delayed trials. We hypothesized that, if nicotine is a genuine cognitive enhancer, its administration would improve antisaccade performance both in smoking and non-smoking participants. A total of 22 patients with schizophrenia (12 smokers and 10 non-smokers) a…
Comparative analysis of biochip mosaic-based indirect immunofluorescence with enzyme-linked immunosorbent assay for diagnosing myasthenia gravis
2021
Background: The detection of anti-acetylcholine receptor (AChR) and anti-muscle-specific tyrosine kinase (MuSK) antibodies is useful in myasthenia gravis (MG) diagnosis and management. BIOCHIP mosaic-based indirect immunofluorescence is a novel analytical method, which employs the simultaneous detection of anti-AChR and anti-MuSK antibodies in a single miniature incubation field. In this study, we compare, for the first time, the BIOCHIP MG mosaic with conventional enzyme-linked immunosorbent assay (ELISA) in the diagnosis of MG. Methods: A total of 71 patients with MG diagnosis were included in the study. Anti-AChR and anti-MuSK antibodies were measured separately by two different ELISA an…