Heterogeneity of 5-HT responsiveness in different segments of rabbit arteries.
The variation in sensitivity to serotonin (5-HT) as assessed by pD2 was investigated in isolated 25 arterial segments of different vascular regions obtained from rabbits. The responses of the vascular rings which were opened by a transverse cut to form rectangular strips were recorded isometrically. pD2 values for 5-HT of thoracic and abdominal aortic segments were significantly greater than those of visceral arterial branches. Maximal contractions produced by 5-HT in visceral segments were higher than those of thoracic and abdominal aortic segments. There was a positive correlation between the pD2 values for 5-HT and the radii and the thickness of the tunica media layer (r = 0.62 and r = 0.54, respectively, P less than 0.05). The results indicate that the activity of 5-HT varies regionally in different segments of the rabbit arteries and the sensitivity to 5-HT of the segments decreases as the radii of the vessels diminish.
Tuncer
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Department of Pharmacology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Yariş
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Kayaalp
S O
SO
D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects / Q000502:physiology; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D001158:Arteries / Q000187:drug effects / Q000502:physiology; D008297:Male; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*
D012701:Serotonin