C. Karlsson et al., Characterization of 5-hydroxytryptamine receptors mediating circular smooth muscle contraction in the human umbilical artery, GYNECOL OBS, 47(2), 1999, pp. 102-107
The study was performed to characterize pharmacologically the contractile 5
-hydroxytryptamine (5-HT) receptors in the circular smooth muscle of the is
olated human umbilical artery. Effects of agonists and antagonists for diff
erent 5-HT receptor subtypes were studied in intact endothelium vessel segm
ents. All agonists induced concentration-dependent circular smooth muscle c
ontractions. The potency was in declining order 5-HT > alpha-methyl-5-HT >
sumatriptan greater than or equal to 2-methyl-5-HT. The effects of 5-HT and
alpha-methyl-5-HT were antagonized by ketanserin, as well as methiothepin,
The contractile effect of sumatriptan was antagonized by methiothepin but
not by ketanserin. The 5-HT3 receptor antagonist, MDL 72222, did not affect
the contraction by any of the agonists, including 2-methyl-5-HT. It is con
cluded that the 5-HT-induced contraction in the circular smooth muscle of t
he human umbilical artery seems to be mediated by a mixed population of 5-H
T1-like receptors and 5-HT2 receptors.