5-Carboxamidotryptamine elicits 5-HT2 and 5-HT3 receptor-mediated cardiovascular responses in the conscious rabbit: Evidence for 5-HT release from platelets

Abstract

The selective '5-HT1-like' receptor agonist 5-carboxamidotryptamine (5-CT, 0.2-1.6 μg/kg bolus i.v.), serotonin (5-HT, 3-10 μg/kg), and phenylbiguanide (10-40 μg/kg) all elicited the 'Bezold-Jarisch-like' bradycardia reflex in conscious rabbits. This reflex was antagonised by the 5-HT3 receptor antagonist, MDL 72222. After autonomic blockade (mecamylamine), 5-CT and 5-HT infusion (i.v.) caused renal artery spasm (Doppler flowmeter) that was antagonised by ketanserin, a 5-HT2-receptor antagonist. Both 5-CT and 5-HT caused 5-HT1-like receptor mediated increases in hindquarter conductance that were unaltered by ketanserin (0.5 mg/kg). The anomalous 5-HT3 and 5-HT2 receptor actions of 5-CT were ..