Adaptation to periodic high-altitude hypoxia inhibits baroreflex vagal bradycardia in rats.
A 3-week course of adaptation to high-altitude hypoxia (4500 m above sea level) inhibited baroreflex vagal bradycardia induced by a rapid rise of systemic blood pressure in conscious rats. Bradycardic responses to electrical stimulation of peripheral end of the right vagus nerve and methacholine (M(2) muscarinic receptor agonist) in hypoxia-adapted rats did not differ from the control. It is concluded that hypoxia inhibits baroreflex vagal bradycardia by acting on a central element of the baroreceptor reflex arch.
Obrezchikova
M N
MN
Department of Human and Animal Physiology, Biological Faculty, M. V. Lomonosov Moscow State University. obreztchikova@mtu-net.ru
Tarasova
O S
OS
Borovik
A S
AS
Koshelev
V B
VB
D000222:Adaptation, Physiological; D000818:Animals; D017704:Baroreflex; D001919:Bradycardia / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology*; D051381:Rats