Mechanism of ergotamine-induced decrease of peripheral systolic blood pressure in man.
We have previously reported a consistent decrease of peripheral-central systolic blood pressure (SBP) gradients after ergotamine. SBP was measured with cuffs and it is unknown whether measured values reflect changes of intra-arterial SBP or increase of vessel wall tone beneath the cuffs. We hence studied the effect of ergotamine tartrate 0.5 mg intravenously on finger-arm systolic gradients after the following procedures: Infiltration around finger arteries with papaverine (n = 2) and dihydralazine (n = 3), occlusion of blood supply to a finger by an inflated cuff before and 2 hours after ergotamine (n = 6). A normal reduction in finger-arm systolic gradients was seen. The ergotamine-induced decrease of peripheral SBP must therefore be due to a fall in peripheral intra-arterial SBP i.e. to contraction of arteries proximal to the digital arteries. Intra-arterial injection of 10 micrograms ergotamine tartrate caused similar decrease in finger-arm systolic gradients as intravenous administration of 0.5 mg (n = 1) indicating a peripheral site of action.
D000328:Adult; D001132:Arm / Q000098:blood supply; D001794:Blood Pressure / Q000187:drug effects*; D004878:Ergotamine / Q000494:pharmacology*; D006801:Humans; D008297:Male; D014665:Vasodilator Agents / Q000494:pharmacology
D014665:Vasodilator Agents; D004878:Ergotamine