Abstract

Studies have been made of the effects produced on muscle and skin blood flow in the hind limb of the dog after intraarterial injection of ergotamine, Hydergine, epinephrine, norepinephrine and methacholine.

The ergot alkaloids had little or no effect on the dilator response to ischemia. After a reduction in response from the control values, the vasodilatation produced by methacholine remained relatively constant.

Ergotamine and Hydergine both had a two-fold effect on the peripheral vascular bed, causing either constriction or dilatation depending on the dose injected. Higher doses caused dilatation.

Ergotamine and Hydergine caused epinephrine reversal, norepinephrine blockade, epinephrine blockade and norepinephrine reversal in the skin. However, Hydergine did not reverse epinephrine in the muscle. This ineffectiveness of Hydergine was probably related to the potent dilator effect of Hydergine per se.