Untersuchungen zur Acetylcholin-Wirkung auf die Vena portae des Meerschweinchens
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Some characteristics of cholinergic effects on the portal vein of the guinea pig
Cholinergic effects on spontaneously active isolated segments of guinea-pig portal vein were studied by long-term intracellular measurements of membrane potential and simultaneous recordings of mechanical activity.
Acetylcholine induces a strengthening of spontaneous activity: a decrease of the basic membrane potential is associated with an increase in spike frequency and a rise in tension. After repeated acetylcholine-applications, a marked tachyphylactic effect was observed.
Reactions to acetylcholine were not affected either by a nerve blocking agent (tetrodotoxin) or by an adrenergic blocking agent (phentolamine).
Reactions to acetylcholine were markedly reduced or abolished by atropine.
The results give evidence of a “muscarinic” mechanism, which means a direct effect of acetylcholine on the membrane of the muscle cells. This indicates the existence of similarities to intestinal muscle and suggests less specificity of the smooth muscle of portal vein.
Key-WordsSmooth Muscle Portal Vein Spontaneous Activity Acetylcholine “Muscarinic” Effect
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- Bolton, T. B.: Electrical and mechanical activity of the longitudinal muscle of the anterior mesenteric artery of the domestic fowl. J. Physiol. (Lond.)196, 283–292 (1968).Google Scholar
- Ferry, C. B.: The sympathomimetic effect of acetylcholine on the spleen of the cat. J. Physiol. (Lond.)167, 487–504 (1963).Google Scholar
- Funaki, S., Bohr, D. F.: Electrical and mechanical activity of isolated vascular smooth muscle of the rat. Nature (Lond.)203, 192–194 (1964).Google Scholar
- Golenhofen, K., Loh, D. v.: Intracelluläre Potentialmessungen zur normalen Spontanaktivität der isolierten Portalvene des Meerschweinchens. Pflügers Arch.319, 82–100 (1970a).Google Scholar
- ——: Elektrophysiologische Untersuchungen zur normalen Spontanaktivität der isolierten Taenia coli des Meerschweinchens. Pflügers Arch.314, 312–328 (1970b).Google Scholar
- Holman, M. E.: Electrophysiology of vascular smooth muscle. Ergebn. Physiol.61, 137–177 (1969).Google Scholar
- —, McLean, A.: The innervation of sheep mesenteric veins. J. Physiol. (Lond.)190, 55–69 (1967).Google Scholar
- Iversen, L. L.: The catecholamines. Nature (Lond.)214, 8–14 (1967).Google Scholar
- Johansson, B., Bohr, D. F.: Rhythmic activity in smooth muscle from small subcutaneous arteries. Amer. J. Physiol.210, 801–806 (1966).Google Scholar
- Keatinge, W. R.: Electrical and mechanical responses of arteries to stimulation of sympathetic nerves. J. Physiol. (Lond.)185, 701–715 (1966).Google Scholar
- Lande, I. S. de la, Rand, M. I.: A simple isolated nerve-blood vessel preparation. Aust. J. exp. Biol. med. Sci.43, 639–656 (1965).Google Scholar
- Loh, D. v.: The effect of adrenergic drugs on spontaneously active vascular smooth muscle studied by long-term intracellular recording of membrane potential. Basel-New York: S. Karger 1971 (im Druck).Google Scholar
- Nakajima, A., Horn, L.: Electrical activity of single vascular smooth muscle fibers. Amer. J. Physiol.213, 25–30 (1967).Google Scholar
- Steedman, W. M.: Micro-electrode studies on mammalian vascular muscle. J. Physiol. (Lond.)186, 382–400 (1966).Google Scholar
- Uchida, E., Bohr, D. F.: Myogenic tone in isolated perfused resistance vessels from rats. Amer. J. Physiol.216, 1343–1350 (1969).Google Scholar