Contractile responses and noradrenaline release evoked by serotonin in cat femoral artery: influence of pentobarbital.
1. 5-Hydroxytryptamine (5-HT) induced dose-dependent contractions in the isolated cat femoral artery, which were reduced by LSD, methysergide, phentolamine and reserpine pretreatment (only at low doses). 2. Pentobarbital (PB) and Mn/+ relaxed the arteries previously contracted with 5-HT. These drugs reduced the contraction evoked by this amine as it was Ca2+-suppression. 3. High concentrations of 5-HT and K+ induced tritium release from vessels prelabelled with 3H-noradrenaline. Ca2+-deprivation and PB unmodified the release caused by 5-HT, but that elicited by K+ was abolished. 4. These data indicate that 5-HT-induced contraction is essentially due to direct interaction of this agent with 5-HT-receptors, and that PB interferes with Ca2+ entry to the cell.
D000818:Animals; D001808:Blood Vessels / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002415:Cats; D005263:Femoral Artery / Q000187:drug effects; D066298:In Vitro Techniques; D008345:Manganese / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D010424:Pentobarbital / Q000494:pharmacology*; D011941:Receptors, Adrenergic / Q000187:drug effects; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology* / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects*
D002121:Calcium Channel Blockers; D011941:Receptors, Adrenergic; D011985:Receptors, Serotonin; D012701:Serotonin; D008345:Manganese; D010424:Pentobarbital; D002118:Calcium; D009638:Norepinephrine