Effects of Changes in CNS Catecholamine on Baroreflex Sensitivity and Cerebral Blood Flow in Rabbit
1988 Volume 47 Issue Suppl-4 Pages 45-50
Details
1988 Volume 47 Issue Suppl-4 Pages 45-50
The effects of 6-hydroxydopamine (6-OHDA) and amphetamine on baroreflex sensitivity (BRS), blood pressure (BP) and brain stem PO2 tension were studied in conscious rabbits. 6-OHDA, which produces chronic degeneration of catecholamine (CA) nerve terminals was injected into a lateral ventricle of the brain. The facilitation of CNS CA release was produced by intravenous injection of amphetamine.BRS was calculated from changes in the BP after the injection of norepinephrine (NE) or nitroglycerine. Following 6-OHDA administration, BRS became significantly higher and BP fluctuation was minimum for one hour in loosely restrained rabbits. On the other hand, amphetamine inhibited the BRS and caused large fluctuations of BP, as has been shown in other reports. Furthermore, decreases of BP and brain stem PO2 were observed when passive head up tilt (45 degrees) was performed quickly in rabbits with lower BRS.
These findings suggest that brain stem blood flow is hampered by disturbances of BRS caused by prolonged exposure to stressfull conditions.
