Evidence that the P1-purinoceptor in the guinea-pig taenia coli is an A2-subtype
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منابع مشابه
Inhibitory mechanisms of isoprenaline in the guinea-pig taenia coli.
The beta-receptor stimulating effect of isoprenaline on the spontaneous activities of the guinea-pig taenia coli was investigated in the presence of an alpha-receptor blocking agent, phentolamine (2 X 10(-6) M). Substitution of the external Naion with Li, choline, tris-hydroxymethyl aminomethane or Kion greatly reduced the inhibitory effect of isoprenaline. A treatment with ouabain (4 X 10(-6) ...
متن کامل[Relaxing effect of isoprenaline on the contracture of the guinea-pig taenia coli].
The relaxing effect of isoprenaline on [Na+]o-free induced contracture of the guinea-pig taenia coli was investigated in presence of phentolamine (10(-5)M), an alphareceptor blocking agent. This action of isoprenaline showed dose-dependency (ED 50: 10(-5)M) and was abolished completely by beta-receptor blocking agent (propranolol, 10(-5)M). The effect of isoprenaline (10(-5)M) disappeared gradu...
متن کاملCaffeine and Excitation-Contraction Coupling in the Guinea Pig Taenia Coli
The effects of caffeine (0.2-10 mM) on the electrical and mechanical activities of guinea pig taenia coli were investigated with the double sucrose-gap method. Caffeine evoked a small tension with a latency of 20-30 sec, then phasic contraction developed and finally relaxation. The initial tension development also appeared in the Na-free solution without any marked changes in the membrane poten...
متن کاملOutward current in single smooth muscle cells of the guinea pig taenia coli
In single myocytes of the guinea pig taenia coli, dispersed by enzymatic digestion, the late outward current is carried by K+. It has both a Ca2+-activated component and a voltage-dependent component which is resistant to external Co2+. The reversal potential is -84 mV, and the channel(s) for it are highly selective to K+. At 33 degrees C, the activation follows n2 kinetics, with a voltage-depe...
متن کاملDesensitization of smooth muscle cells in the guinea pig taenia coli to prolonged application of carbachol.
depolarized the membrane, reduced the membrane resistance and evoked contracture. These responses did not, however, continue but a desensitization to Carb then developed, i. e. the membrane was gradually repolarized, membrane resistance increased, and the muscle relaxed in spite of the presence of Carb. 2. During the repolarization phase in the presence of Carb (10-5 g/ml), repeated current pul...
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ژورنال
عنوان ژورنال: British Journal of Pharmacology
سال: 1984
ISSN: 0007-1188
DOI: 10.1111/j.1476-5381.1984.tb10106.x