Evidence for L-glutamate as the neurotransmitter of baroreceptor afferent nerve fibers.

Microinjection of L-glutamate into the intermediate nucleus tractus solitarii in anesthetized rats elicits hypotension, bradycardia, and apnea, simulating baroreceptor reflexes. Ablation of the nodose ganglion results in selective reduction of high-affinity uptake of L-glutanate in the nucleus tractus solitarii. L-Glutamate may be the neurotransmitter of afferent nerve fibers from arterial baroreceptors.