Involvement of caudal ventrolateral medulla neurons in mediating visceroreceptive information to the hypothalamic paraventricular nucleus.

Both neurohypophyseal and tuberoinfundibular neurosecretory neurons in the PVN received excitatory synaptic inputs from the CVLM. We electrophysiologically identified neurons in the CVLM which project to the PVN. On the basis of antidromic spike latencies, two different populations of neurons could be differentiated: slow- and fast-conducting cells. Slow-conducting cells which were presumed to be A1 catecholaminergic cells, received inhibitory and excitatory synaptic inputs from arterial baroreceptors and the cervical vagus nerve, respectively. Our results suggest that slow conducting cells in the CVLM which cause excitation of PVN neurons via a monosynaptic pathway, mediate visceroreceptive information to the PVN.