Activation of sustained sympathetic vasodilatation in dog by spinal cord stimulation

Abstract

Electrical stimulation in lateral sites of the upper cervical spinal cord evoked vasodilatation after adrenergic blockade. Sympathetic fibres mediating sustained vasodilatation were shown to be separate from adrenergic sympathetic fibres since the adrenergic vasoconstrictor response in the paw evoked by vasomotor stimulation in the medulla was not reversed to vasodilatation after bretylium.

Cardiovascular Adjustments to Heat Stress

“…Similarly, Green et al (83) found no evidence for sympathetic vasodilator innervation of the dog paw. In contrast, Zimmerman and colleagues (142,212,213,274) reported a series of studies strongly supportive of the existence of a non-cholinergic, nonadrenergic, nonhistaminergic vasodilator system in the dog paw. This system was revealed through direct stimulation of sympathetic nerves following blockade of transmitter release from adrenergic nerves with bretylium.…”