Search results for "Musca"
showing 10 items of 300 documents
A muscarinic receptor different from the M1, M2, M3 and M4 subtypes mediates the contraction of the rabbit iris sphincter
1992
In order to analyse the subtype of muscarinic receptors involved in the methacholine-induced contraction of the rabbit iris sphincter we have determined equilibrium dissociation constants (KB) of various antagonists in the sphincter muscle. The values were compared with those observed at M1 (rabbit vas deferens), M2 (heteroreceptors in rat iris) and M3 receptors (guinea-pig ileum), or at the muscarinic receptors in the guinea-pig uterus. The methacholine-induced contraction of the uterus from immature guinea-pigs was competitively antagonized by pirenzepine (6.64, -log KB), 4-DAMP (8.39), hexahydrodifenidol (HHD; 7.00 for the (R)- and 5.40 for the (S)-enantiomer), p-fluoro-hexahydrosiladife…
Enhancement of guinea-pig intestinal peristalsis by blockade of muscarinic M1-receptors
1988
1. The effects of pirenzepine and hyoscine on the peristaltic reflex were investigated in the guinea-pig isolated small intestine. Peristalsis was induced by raising the intraluminal pressure and the volume of fluid propelled was taken as a measure of the efficiency of peristaltic activity. 2. Low concentrations of pirenzepine (0.1-1 nM) and of hyoscine (0.01 nM) significantly enhanced peristalsis, whereas larger concentrations of both drugs caused inhibition. Pirenzepine was about 6 times less potent than hyoscine in increasing peristalsis, but was about 100 times less potent in inhibiting it. 3. Neither tolazoline (1 microM) nor naloxone (0.3 microM) affected the stimulatory action of pir…
Muscarinic inhibition of acetylcholine release from a novel in vitro preparation of the guinea-pig trachea
1990
An isolated preparation of the guinea-pig trachea is described which allows the simultaneous measurement of acetylcholine release and smooth muscle contraction. Incubation of the epithelium-free preparation with [3H]choline resulted in the formation of [3H]acetylcholine. Electrical stimulation caused the release of [3H]acetylcholine and a contractile response. Tetrodotoxin and omission of calcium from the medium abolished both the evoked release and contractions. The muscarinic agonists oxotremorine, carbachol and pilocarpine concentration-dependently inhibited the electrically evoked acetylcholine release and contracted the tracheal smooth muscle. Pre- and postsynaptic EC50 values for a gi…
A useful muscarinic parameter and the differential recording of atrial and ventricular tension in the perfused rabbit heart
1971
1. A simple method of recording right atrial tension from the Langendorff perfused rabbit has been described; it is based on the “transverse” method of recording cardiac contractions described by Beckett (1970). 2. Right atrial and ventricular tensions were recorded by transducers attached to threads stitched into the right atrium and right ventricle, the heart being retained and prevented from rotating by two threads stitched into the intraventricular septum as described by Beckett. 3. Right ventricular diastolic tension was adjusted to 7.5 g. Interference with the atrial record by ventricular systole was overcome by adjustment of diastolic right atrial tension to its optimal value between…
Muscarinic inhibition of endogenous noradrenaline release from rabbit isolated trachea: receptor subtype and receptor reserve.
1994
The aim of the present study was to characterize putative muscarine receptors on sympathetic nerve terminals in the rabbit trachea. Release of endogenous noradrenaline from in vitro incubated rabbit trachea was evoked by electrical field stimulation (3 Hz, 540 pulses) and quantified by high performance liquid chromatography with electrochemical detection. The muscarine receptor agonist oxotremorine inhibited the evoked release of noradrenaline completely at 1 mumol/l (EC50: 64 nmol/l). The concentration response curve was very steep (Hill coefficient of 2.3). Scopolamine shifted the concentration response curve of oxotremorine to the right (-log KB 8.48) demonstrating specific, inhibitory m…
Muscarinic receptors, leukotriene B4 production and neutrophilic inflammation in COPD patients.
2005
Background: Acetylcholine (ACh) plays an important role in smooth muscle contraction and in the development of airway narrowing; preliminary evidences led us to hypothesize that ACh might also play a role in the development of airways inflammation in chronic obstructive pulmonary disease (COPD). Methods: We evaluated the concentrations of leukotriene B4 (LTB4) in induced sputum, and the expression of Ach M1, M2, and M3 receptors in sputum cells (SC) obtained from 16 patients with COPD, 11 smokers, and 14 control subjects. The SC were also treated with ACh and the production of LTB4 assessed in the presence or absence of a muscarinic antagonist (oxitropium). In blood monocytes, we evaluate…
Comparison of octreotide and hyoscine butylbromide in controlling gastrointestinal symptoms due to malignant inoperable bowel obstruction
2000
In advanced cancer patients with inoperable bowel obstruction, the administration of antisecretive and antiemetic drugs has proved to be effective in controlling gastrointestinal symptoms caused by bowel obstruction. However, controlled studies concerning the most effective antisecretive drug are lacking. The aim of this randomized controlled study was to determine whether octreotide or hyoscine butylbromide was the more effective antisecretive drug for use in states of inoperable bowel obstruction. Eighteen patients with inoperable bowel obstruction randomly received octreotide 0.3 mg daily (n = 9) or hyoscine butylbromide (HB) 60 mg daily (n = 9) s.c. The following parameters were measure…
EAU guidelines on the treatment and follow-up of non-neurogenic male lower urinary tract symptoms including benign prostatic obstruction.
2013
To present a summary of the 2013 version of the European Association of Urology guidelines on the treatment and follow-up of male lower urinary tract symptoms (LUTS). We conducted a literature search in computer databases for relevant articles published between 1966 and 31 October 2012. The Oxford classification system (2001) was used to determine the level of evidence for each article and to assign the grade of recommendation for each treatment modality. Men with mild symptoms are suitable for watchful waiting. All men with bothersome LUTS should be offered lifestyle advice prior to or concurrent with any treatment. Men with bothersome moderate-to-severe LUTS quickly benefit from α1-blocke…
Evaluation by reverse phase HPLC of [3H]acetylcholine release evoked from the myenteric plexus of the rat.
1990
Myenteric plexus-longitudinal muscle strips isolated from the small intestine of rats were incubated with [3H]choline to measure the synthesis and the release of [3H]acetylcholine. To separate different radioactive compounds (acetylcholine, choline, phosphorylcholine) from both the tissue and the overflow a new method, the reverse phase HPLC, was used. The radiochromatogram following the injection of a [3H]choline-standard and a [14C]acetylcholine-standard onto the HPLC showed a clear separation of both isotopes with a recovery rate of roughly 100%. Incubation of the muscle strips with [3H]choline caused the synthesis of [3H]acetylcholine (30,000 dpm/preparation) that increased 2-fold, when…
Presynaptic effects of scopolamine, oxotremorine, noradrenaline and morphine on [3H] acetylcholine release from the myenteric plexus at different sti…
1987
The inhibition by three modulators (oxotremorine, noradrenaline, morphine) of acetylcholine release from the myenteric plexus preincubated with [3H]choline was investigated at different stimulation frequencies and calcium concentrations. Moreover, [3H]acetylcholine release evoked by a low (0.1 Hz) or a high (10 Hz) stimulation rate was investigated at different calcium concentrations either in the absence or presence of scopolamine. A reduced calcium concentration (0.6 mmol/l) inhibited acetylcholine release more at 0.1 Hz (74% +/- 3%) than at 10 Hz (44% +/- 8%). Scopolamine enhanced the stimulated acetylcholine release at a calcium concentration of 1.8 mmol/l. At calcium concentrations hig…