An automated superfusion technique for measuring circular muscle contraction. Effects of serotonin on intra- and extracranial arteries.
A new in vitro technique is described and its advantages are demonstrated: "true" circular contraction is measured; arteries are in cascade, permitting comparison of intra- and extracranial arteries from the same animal; the mechanical influences on contractility are reduced; long-lasting experiments of up to 50 h can be performed; the procedure is fully automated. The maximal effect of an agonist was not only markedly modified during the first 2--4 h after fixing the arteries in the apparatus but also slightly during the next 3--4 h. After the initial stabilization period, the arterial response to an agonist remained highly reproducible for 24--48 h (standard deviation not exceeding 7%). This was demonstrated in all the types of arteries tested. With serotonin as agonist, there was a significant difference in --log ED50 values for intracranial arteries (basilar 8.70, middle cerebral 8.72) vs. extracranial (lateral nasal 8.15; facial 8.14) and peripheral (branch of saphenous 8.14) arteries.
D000818:Animals; D001158:Arteries / Q000187:drug effects; D004285:Dogs; D005260:Female; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D010477:Perfusion / Q000379:methods*; D012039:Regional Blood Flow / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology*; D013696:Temperature
D012701:Serotonin