Subfornical organ stimulation excites paraventricular neurons projecting to dorsal medulla.
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.
D000818:Animals; D004558:Electric Stimulation; D006624:Hippocampus / Q000502:physiology; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D009490:Neurosecretory Systems / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000502:physiology*; D010904:Pituitary Gland, Posterior / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time; D013356:Subfornical Organ / Q000502:physiology*; D009435:Synaptic Transmission