Release of 3H-5-hydroxytryptamine from isolated rabbit aorta.
The main aim of the present investigation was to study systematically the passive and stimulation-evoked release of 3H-5-hydroxytryptamine (3H-5-HT) from rabbit isolated aorta. This was accomplished by preloading rings of aorta with 3H-5-HT (10(-6)M) and then monitoring by fractional collection the basal 3H-outflow and stimulation-evoked 3H-overflow. The basal 3H-outflow from aorta preloaded with 10(-6)M of either 3H-5-HT or (-)-3H-noradrenaline (3H-NA) leveled off about 100 min. after the onset of wash-out and remained almost constant thereafter (100-240 min.). The basal 3H-outflow from tissue preloaded with 3H-5-HT was almost 3-fold higher (70-240 min.) than that seen after preloading with 3H-NA. Cocaine (3 x 10(-5)M) did not alter the basal 3H-outflow (15-240 min.) from tissue preloaded with 3H-5-HT, while pargyline (5 x 10(-4)M) decreased it by about 66% (100-240 min.). Electrical-field stimulation (S1-S7, 200 mA, 600 pulses, 0.5 msec., 3 Hz) were applied to the tissue. The initial stimulation-evoked 3H-overflow from aorta preloaded with 3H-5-HT was higher than the subsequent ones (S1-S7; 100, 35, 35, 35, 35, 37, and 40%). Similar results to these were obtained with tissues preloaded with 3H-NA. The stimulation (S1-S7; 200 mA). 600 pulses, 0.5 msec, 3 Hz)-evoked 3H-overflow increased in an apparent linear manner with the amount of current used (50-200 mA).(ABSTRACT TRUNCATED AT 250 WORDS)
Gouliaev
A H
AH
Department of Pharmacology, School of Medicine, Odense University, Denmark.
Nedergaard
O A
OA
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism*; D003042:Cocaine / Q000494:pharmacology; D004558:Electric Stimulation; D004730:Endothelium, Vascular / Q000378:metabolism; D005260:Female; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D016627:Oxidopamine; D010293:Pargyline / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000378:metabolism*; D013563:Sympathectomy, Chemical; D013779:Tetrodotoxin / Q000494:pharmacology
D012701:Serotonin; D013779:Tetrodotoxin; D016627:Oxidopamine; D010293:Pargyline; D003042:Cocaine; D009638:Norepinephrine