Vasoconstrictor Inhibition and Vasodilator Activation — Two Functionally Separate Vasodilator Mechanisms in the Skeletal Muscles.

Summary. Vasodilatation in the skeletal muscles is produced by electric stimulation of a sinus nerve, a vagus nerve, the depressor area of the oblongate medulla or by activation of sympathetic vasodilator nerves. Destruction of the depressor area does not prevent the transmission of impulses in the bulbar sympathetic vasodilator tract. The depressor area and the bulbar part of the sympathetic vasodilator tract seem to be separate anatomical and functional entities. The writers have been unable to activate the two vasodilator mechanisms simultaneously, a fact that is regarded to support the conception that they form two independently operating mechanisms. The expenses of this investigation were partly defrayed by a grant from the Swedish Medical Research Council to one of us (B. U.) which is gratefully acknowledged.