Search results for "Musca"
showing 10 items of 300 documents
The effect of physostigmine on the vagally induced muscarinic inhibition of noradrenaline release from the isolated perfused rabbit atria.
1982
1. Presynaptic cholinergic-adrenergic interactions were studied on isolated perfused rabbit atria with the extrinsic right vagus and sympathetic innervation intact. The transmitter stores were labelled with 14C-choline and 3H-noradrenaline. The radioactive compounds were separated on columns and determined by scintillation spectrometry. The stimulation-evoked overflow of both transmitters was calcium-dependent and abolished by tetrodotoxin. 2. Methacholine caused a concentration-dependent decrease of atrial tension development and 3H-noradrenaline overflow evoked by 3 Hz sympathetic stimulation. Vagus nerve stimulation (1–20Hz), although nearly abolishing tension development at 20Hz, decrea…
Suppression by cholinesterase inhibition of a Ca(2+)-independent efflux of [3H]acetylcholine from the neuromuscular junction of the isolated rat diap…
1992
Abstract Endplate preparations of the left rat hemidiaphragm were incubated with [ 3 H]choline to label neuronal acetylcholine stores. Elevation of the concentration (13.5–135 mmol/l) of extracellular potassium chloride (KC1) stimulated the release of [ 3 H]acetylcholine in a concentration-dependent manner. KC1 (27 mmol/l) still caused a significant efflux of [ 3 H]acetylcholine in a Ca 2+ -free medium. Inhibitors of cholinesterase (physostigmine, diisopropylfluorophosphate) suppressed by 80% this Ca 2+ -independent efflux of [ 3 H]acetylcholine. Vesamicol (10 μmol/l), the blocker of the vesicular acetylcholine carrier, also suppressed the stimulated, Ca 2+ -independent efflux of [ 3 H]acet…
Some pharmacological properties of the false cholinergic transmitter acetylpyrrolidinecholine and its precursor pyrrolidinecholine
1976
The acetylchline analogue acetylpyrrolidinecholine as well as the choline analogue pyrrolidinecholine were synthesized and the cholinergic properties of both substances were investigated on the guinea-pig ileum, rat blood pressure and frog rectus abdominis muscle. Acetylpyrrolidinecholine was 3-5 times less potent than acetylcholine on the three preparations tested. The dose-response curves to acetylpyrrolidinecholine were shifted to the right in a parallel manner by atropine and (+)-tubocurarine. The dissociation constants for atropine and (+)-tubocurarine obtained with acetylpyrrolidinecholine as agonist were not different from those obtained with acetylcholine. This indicates that acetyl…
Does concomitant diabetes affect treatment responses in overactive bladder patients?
2013
Summary Aims To compare the efficacy and tolerability of a muscarinic receptor antagonist, darifenacin, in the treatment of overactive bladder (OAB) patients with concomitant diabetes as compared with those without comorbidities. Methods Post hoc exploratory analysis of a published, large, non-interventional study in OAB patients treated with darifenacin including 532 diabetics and 1315 controls. Associations of diabetes with treatment responses were evaluated by multiple regression models. Results Diabetics (largely type 2 patients) and controls differed in baseline age, body weight, duration of OAB symptoms and presence of comedications. However, they exhibited similar OAB symptom episode…
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…
Sympathetic Nerve Stimulation on the perfused rat heart. Affinities of N-methylatropine and pirenzepine at pre- and postsynaptic muscarine receptors.
1982
Rat isolated hearts with the sympathetic nerves attached were perfused with (-)-3H-noradrenaline in order to label the storage vesicles of the adrenergic nerves. Release was induced either by electrical stimulation of the nerves (3 Hz, 1 min) or by perfusion with high K+ solution (54 mM). The overflow of 3H-noradrenaline and its metabolites was determined by liquid scintillation counting after separation of the compounds by column chromatography. The experimental conditions ensured a minor contribution of 3H-metabolites to the evoked total tritium overflow. The release of 3H-noradrenaline evoked by nerve stimulation or high K+ solution was decreased in the presence of the muscarinic agonist…
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…