AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 6 1088-R1092, Copyright © 1984 by American Physiological Society
Subfornical organ stimulation excites paraventricular neurons projecting to dorsal medulla
A. V. Ferguson, T. A. Day and L. P. Renaud
Electrical stimulation in the subfornical organ (SFO) of
pentobarbital-anesthetized Sprague-Dawley rats was noted to influence the
excitability of paraventricular nucleus (PVN) neurons antidromically
identified as projecting to the dorsomedial medulla. Extracellular
recordings indicated that 60% (n = 34) of these caudally projecting PVN
neurons increased activity in response to single shock stimuli delivered to
the SFO. Short-latency [30.0 +/- 2.7 (SE) ms] and long-latency (162.5 +/-
32.5 ms) responses were observed. The remaining neurons were either
unaffected (38%) or inhibited (2%) by SFO stimulation. These data suggest
functional connectivity between the SFO and the dorsomedial medulla. It is
proposed that such a pathway may mediate pressor responses observed to
follow electrical stimulation in the SFO.
