Differential responses of barosensitive neurons of rostral ventrolateral medulla to hypoxia in rats.
We examined the responses to hypoxia of 48 spontaneously active barosensitive neurons of the rostral ventrolateral medulla (RVL) of anesthetized rats. Twenty-nine projected to the spinal cord while 19 did not. All spinal barosensitive neurons increased their discharges in advance of an elevation of arterial pressure in the presence or absence of arterial chemoreceptors. In contrast, 18/19 of the non-spinal barosensitive neurons were not excited by hypoxia. The results indicate that barosensitive RVL neurons consist of two populations differing in efferent pathway and responsivity to hypoxia and that the spinal barosensitive RVL neurons are functionally discrete and selectively sensitive to hypoxia.
Sun
M K
MK
Department of Neurology and Neuroscience, Cornell University Medical College, New York, NY 10021.
Reis
D J
DJ
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002628:Chemoreceptor Cells / Q000502:physiology; D003714:Denervation; D004525:Efferent Pathways / Q000502:physiology; D002534:Hypoxia, Brain / Q000503:physiopathology*; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D011311:Pressoreceptors / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000502:physiology; D013238:Stereotaxic Techniques; D013564:Sympathetic Nervous System / Q000502:physiology