Search results for "guinea"
showing 10 items of 412 documents
MONENSIN ENHANCES DIGOXIN-INDUCED ARRHYTHMIAS IN GUINEA-PIGS
1993
Effects of pretreatment with monensin (150 ug/kg), atenolol (0.3 mg/kg), atenolol plus monensin, verapamil (0.38 mg/kg), verapamil plus monensin, glibenclamide(0.38 mg/kg) and glibenclamide plus monensin on the dose of digoxin required to induce premature ventricular contractions (PVCS) in anaesthetized guinea-pigs were studied. Monensin reduced while atenolol increased the dose of digoxin required to produce PVCS. Atenolol plus monensin increased the dose of digoxin required to produce PVCS in presence of monensin alone. Verapamil reduces the arrhythmogenic effect of monensin on digoxin. Glibenclamide antagonises the effect of monensin on digoxin induced PVCS. From the present data it coul…
Synthese und pharmakologische Wirkung von carbocyclischen Muskarinanalogen
1974
Als carbocyclische Muskarinanaloga wurden das (3-Hydroxycyclopentylmethyl)trimethyl-ammonium-jodid und dessen Acetat dargestellt und am isolierten Ileum des Meerschweinchens untersucht. Synthesis and Pharmacological Activity of Carbocyclic Analogs of Muscarine As carbocyclic analogs of muscarine (3-hydroxycyclopentylmethyl)trimethylammonium iodide and (3-acetoxycyclopentylmethyl)trimethylammonium iodide were synthesized and tested on the isolated guinea pig ileum.
Äther und Ester des 4-(2-Hydroxyaethyl)-imidazols und Ester der 4-Imidazolpropionsäure 4. Mitt. über Struktur-Wirkungs-Beziehungen bei Histaminanaloga
1974
Als potentiell histaminartig wirksame Substanzen wurden Ather und Ester des 4-(2-Hydroxyaethyl)-imidazols und Ester der 4-Imidazolpropionsaure dargestellt und am isolierten Ileum des Meerschweinchens und anderen Testobjekten untersucht. Ethers and Esters of 4-(2-Hydroxyethyl)-imidazole and Esters of 4-Imidazolepropionic Acid As substances with possible histamine-like activity, ethers and esters of 4-(hydroxyethyl)-imidazole and esters of 4-imidazolepropionic acid are prepared and tested on isolated guinea pig ileum and other objects.
Carcinogenic aspect of xenobiotic molecules belonging to the peroxisome proliferator family.
1999
It is known that a short-term exposure of rat, mice or incubation of hepatic cells with fibrate molecules leads to increase in peroxisome number and cell hyperplasia. Further, long-term incubation of cells (at least a year) show transformed characteristics with foci and nodules. To explain the hepatocarcinogenic effect of peroxisome proliferators in rodents we studied the effect of peroxisome proliferators on rat liver oncogenes expression. Earlier, we reported an increase in liver and kidney mRNA level of c-myc and N-myc. Since several metabolic genes are activated by PPAR (peroxisome proliferators activated receptor) through a PPRE (peroxisome proliferator response element), we suggest th…
Alteration of loosely bound calcium in the guinea pig organ of Corti after treatment with diltiazem as calcium channel blocker
1997
After oral administration of the organic calcium channel blocker diltiazem to guinea pigs for 7 days, calcium ions were precipitated with potassium antimonate in the cochleae. The spatial distribution of the precipitates was studied by energy-filtering transmission electron microscopy and the amount of the ultrastructural reaction products formed was determined semiquantitatively by an image processing system. Compared with untreated control ears, the number of the formed precipitates was reduced drastically in the inner hair cells after diltiazem treatment. In addition, electron microscopic analysis revealed that the number of calcium precipitates attached at the basolateral membrane of th…
Characterization of adenosine receptors in guinea-pig isolated left atria
1989
1. The effects of purinergic stimulation on action potential, force of contraction, 86Rb efflux and 45Ca uptake were investigated in guinea-pig left atria. 2. Adenosine exerted a negative inotropic effect which was antagonized by adenosine deaminase but enhanced by dipyridamole. 3. The negative inotropic effect of adenosine was mimicked by 5'-(N-ethyl)-carboxamido-adenosine (NECA) and the isomers of N6-(phenyl-isopropyl)-adenosine, R-PIA and S-PIA. NECA and R-PIA were about 100 times more potent than adenosine, whereas R-PIA was about 100 times more potent than S-PIA. 4. The inotropic effects of adenosine (in the presence of dipyridamole), NECA, R-PIA and S-PIA were competitively antagonize…
Adrenoceptor-mediated effects on calcium channel currents are antagonized by 5?-(N-ethyl)-carboxamido-adenosine in guinea-pig atrial cells
1992
In guinea-pig atrial myocytes, the effects of the adenosine analogue 5′-(N-ethyl)-carboxamido-adenosine (NECA) in the presence of isoprenaline (ISO) on Ca2+ channel activity were analyzed. Single Ca2+ channel currents were recorded from cell-attached patches by application of several hundred 100 ms depolarizing steps. Under control conditions, burstlike activity of channel openings during some depolarizing steps were followed by variably long periods of quiescence (blank sweeps). During superfusion with ISO (100 nmol/l), ensemble-averaged (mean) current was increased by about 150%. The underlying mechanism was found to be a significant increase in the channel availability, defined as the ra…
Tachykinin-, calcitonin gene-related peptide-, and protein gene product 9.5-immunoreactive nerve fibers in alveolar walls of mammals.
1991
The presence and distribution of the presumed pan-neural marker protein gene product 9.5 (PGP)- and peptide-immunoreactive (ir) nerve fibers in alveolar walls of various species was investigated by light microscopic single and double staining immunohistochemistry. PGP-, tachykinin (TK)-, and calcitonin gene-related peptide (CRGP)-ir fibers were sparsely distributed in a similar pattern in alveolar walls of all species investigated. No vasoactive intestinal peptide-, peptide histidine isoleucine-, galanin-, and opioid-ir nerve fibers could be detected. PGP-ir fibers outnumbered those staining for TKs and CGRP. There was partial coexistence of PGP and TK as well as of TK and CRGP. PGP-, TK-, …
Analysis of the hyperpolarizing effects of forskolin in guinea-pig atrial heart muscle.
1988
The effects of forskolin on action potential configuration and on both uptake and efflux of 86Rb+ were studied in guinea-pig left atria. The action potential was prolonged by forskolin in the plateau range but shortened at the end of repolarization; maximal upstroke velocity and amplitude of slow response potentials were enhanced. In partially depolarized preparations, the resting potential was increased by forskolin; this effect was not prevented by atropine 1 μmol/1. Forskolin augmented the rate constant of 86Rb+ efflux in beating and in resting preparations. The uptake of 86Rbs+ was enhanced by forskolin in resting preparations. It is concluded that forskolin stimulates the Na+, K+ -pump…
Pre- and postsynaptic effects of muscarinic agonists in the guinea-pig ileum
1980
The effects of several muscarinic agonists on smooth muscle (postsynaptic effect) and on acetylcholine release (presynaptic effect) were compared in the longitudinal muscle-myenteric plexus preparation of the guinea-pig ileum. 1. For release experiments the acetylcholine stores of the preparation were labelled with 3H-choline. Electrical field stimulation in the absence of a cholinesterase inhibitor caused an outflow of tritium that reflected release of 3H-acetylcholine. The agonists oxotremorine, arecaidinepropargylester, methylfurmethide, muscarine, carbachol, arecoline and pilocarpine inhibited the stimulation-induced outflow in a concentration-dependent manner. At the highest concentrat…