Fig. 3

Effect of i.v. bolus injections of isometheptene enantiomers or the racemate (3 mg/kg) on dural vasodilation induced by periarterial electrical stimulation (150–300 μA, upper panels), capsaicin (10 μg/kg, middle panels) or α-CGRP (1 μg/kg, lower panels) in anesthetized rats (n = 4 in each group); (S)-IMH, (S)-isometheptene; (R)-IMH, (R)-isometheptene; (RS)-IMH, isometheptene racemate