The excitatory response of the adrenal sympathetic nerve to severe hypoxia decreases in aged rats.
The age-related changes in the sensitivity of the adrenal sympathetic nerve to hypoxia were investigated in anesthetized young adult (3-4 months old) and aged rats (25-26 months old). Hypoxia with end-tidal O2 concentration (FETO2) at 6-2% caused excitation of adrenal nerve activity in the young adult and the aged rats. There was a significant decrease in the responses at 3 and 2% FETO2 in the aged rats compared to the young adult rats at either peripheral chemoreceptors-intact or -denervated condition. Reduced responsiveness of the central chemoreceptors to severe hypoxia is suggested as a possible factor in the age-related decreases.
Sato
A
A
Department of the Autonomic Nervous System, Tokyo Metropolitan Institute of Gerontology, Japan.
Trzebski
A
A
D000313:Adrenal Medulla / Q000294:innervation*; D000375:Aging; D000818:Animals; D002628:Chemoreceptor Cells / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex; D013564:Sympathetic Nervous System / Q000503:physiopathology*