Participation of ventrolateral medullary neurons in the renal-sympathetic reflex in XXXX .

@entity1026 @entity8 @entity2227 @entity1246 @entity1027 @entity4774 @entity95 @entity3897 @entity5373
In an effort to locate medullary structures that mediate the renal-sympathetic reflex, the effect, on the excitatory (E) and inhibitory (I) components of that reflex, of certain drugs applied to the ventral surface of the medulla was investigated in @entity4774 -anesthetized and vagotomized @entity95 . Application of @entity1027 , a @entity1246 receptor antagonist, selectively abolished the I component of the renal-sympathetic reflex as well as the sympathoinhibition elicited by stimulation of the aortic nerve. The E component, on the other hand, was specifically eliminated by @entity5373 , a @entity2227 receptor antagonist. @entity1026 or @entity3897 did not affect either reflex appreciably. Subsequently, within the region of the ventrolateral medulla (VLM) subjacent to the site of drug applications, we searched for neurons which responded to stimulation of the @entity8 . Of 68 responsive VLM neurons found, 50 (73.5%) responded to stimulation of both nerves. Of the 50 neurons, 40 were tested for their antidromic activation to stimulation of the spinal cord. Twenty-four neurons (60%) were antidromically activated. Responses of these reticulospinal neurons to stimulation of the renal nerve preceded that of @entity8 ( @entity8 ) by about 100 ms. All the antidromically activated, VLM neurons which responded to stimulation of the renal nerve also responded to stimulation of the aortic nerve. In conclusion, the renal-sympathetic reflex appears to be mediated by the same pool of bulbospinal neurons in the ventrolateral medulla that mediates the arterial baroreceptor reflex, and the E and I components of that reflex can be selectively abolished by pharmacological intervention of the subjacent ventral surface of the medulla.
