Effect of chemical sympathectomy on cerebral blood flow in rats.
Thirty male Wistar rats, weighing 350 to 400 gm each, received stereotactic injections of 6-hydroxydopamine (300 micrograms/kg) into the left lateral ventricle. The same amount of saline was injected into a control group of 15 rats. Seven days after this procedure, cerebral blood flow (CBF) was measured by the hydrogen clearance method. A hypertensive condition at a mean arterial pressure of about 160 mm Hg was maintained for 1 hour by intravenous infusion of phenylephrine. In the 6-hydroxydopamine-treated group, CBF increased significantly after the elevation of systemic blood pressure compared with that in the control group, and cerebral autoregulation was impaired. After a 1-hour study, the specific gravity of the cerebral tissue in the treated group significantly decreased; electron microscopic studies at that time revealed brain edema. It is suggested that depletion of brain noradrenaline levels causes a disturbance in cerebral microvascular tone and renders the cerebral blood vessels more vulnerable to hypertension.
Department of Neurosurgery, Fukui Medical School, Matsuoka, Japan.
H
H
Kobayashi
M
M
Hayashi
H
H
Kawano
Y
Y
Handa
M
M
Kabuto
H
H
Ide
D000818:Animals; D001929:Brain Edema / Q000139:chemically induced; D002536:Cerebral Arteries / Q000187:drug effects / Q000294:innervation*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D006706:Homeostasis / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D009638:Norepinephrine / Q000502:physiology; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D013046:Specific Gravity / Q000187:drug effects; D013238:Stereotaxic Techniques; D013563:Sympathectomy, Chemical
D016627:Oxidopamine; D009638:Norepinephrine