Evidence for serotonin (5-HT) sub(1B), 5-HT sub(1D) and 5-HT sub(1F) receptor inhibitory effects on trigeminal neurons with craniovascular input

Development of serotonin (5HT sub(1B/1D)) agonists for the acute attack of migraine resulted in considerable interest in their action. The superior sagittal sinus (SSS) was isolated in alpha -chloralose (60 mg/kg, i.p. and 20 mg/kg i.v.i. supplementary 2 hourly) anaesthetised cats. The de la was stimulated electrically (100 V, 250 mu s duration, 0.3 Hz) and neurons of the trigeminocervical complex monitored using electrophysiological methods. To test 5-HT sub(1B) receptor-mediated activity common carotid blood flow (CCF) was monitored with a transonic flow probe placed around the vessel. Naratriptan (5- HT sub(1B/1D/1F) receptor agonist) and alniditan (5-HT sub(1B/1D) receptor agonist) produced reductions in carotid blood flow of 38+/-5% and 42+/-6%, respectively. These effects were attenuated by the 5-HT sub(1B) receptor antagonist SB224289 (P