Calcium-dependent contractile activation of cerebral artery produced by quick stretch.
Quick stretch of helical strips of rabbit basilar artery at a rate of 4-50 cm/s to 140% of the initial muscle length evoked phasic contraction. The contraction was potentiated by cardiac glycosides, tetraethylammonium, and high K+, all of which augment transmembrane influx of Ca2+, and the enhanced response was suppressed by Ca2+-antagonists such as verapamil and nifedipine. The stretch-induced contraction in Ca2+-free medium was progressively reduced depending on the number of stretches during the observation period of 90 min. The response to quick stretch in Ca2+-free solution was enhanced by norepinephrine or histamine but was not affected by high K+ (40-100 mM), verapamil, or nifedipine. These results suggest that contraction of rabbit basilar artery produced by quick stretch depends not only on transmembrane supply of Ca2+ but also on release of Ca2% bound to the membrane or in internal depots. It also seems possible that, in addition to depolarization of the membrane, mechanical deformation itself triggers the release of Ca2+.
D000588:Amines / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002301:Cardiac Glycosides / Q000494:pharmacology; D002536:Cerebral Arteries / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D009994:Osmolar Concentration; D010812:Physical Stimulation; D011188:Potassium / Q000494:pharmacology; D011343:Procaine / Q000494:pharmacology; D011817:Rabbits; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013997:Time Factors
D000588:Amines; D002301:Cardiac Glycosides; D013757:Tetraethylammonium Compounds; D011343:Procaine; D019789:Tetraethylammonium; D011188:Potassium; D002118:Calcium