title: Local blood flow, cerebrovascular autoregulation and CO2 responsiveness in the rabbit hypothalamus.
abstract: 1. Local blood flow has been measured in the hypothalamus and other areas of the brain in the conscious rabbit, by measuring the rate of clearance of small volumes (2.5-10 mul.) of a saline solution of the inert tracer (133)Xe injected locally.2. Increasing the arterial P(CO2) caused a mean rise in the hypothalamic blood flow of 34%.3. The hypothalamic blood flow remained relatively constant over a mean arterial blood pressure range of 41-140 mm Hg.4. Hypothalamic blood flow was relatively unaffected by anaesthesia with intravenous pentobarbitone; by contrast, blood flow in the cerebral cortex was greatly reduced.5. It is concluded that the technique is a valid and useful one, since CO(2) responsiveness and autoregulation is maintained. Different areas of grey matter have different flow rates, and vary in their responsiveness to barbiturate anaesthesia.
mesh_terms: D000768:Anesthesia, General; D000818:Animals; D001158:Arteries; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood* / Q000378:metabolism; D002540:Cerebral Cortex / Q000098:blood supply; D002560:Cerebrovascular Circulation; D007031:Hypothalamus / Q000098:blood supply*; D008297:Male; D008657:Metabolic Clearance Rate; D010424:Pentobarbital; D011817:Rabbits; D011868:Radioisotopes; D012039:Regional Blood Flow; D014978:Xenon
chemical_list: D011868:Radioisotopes; D002245:Carbon Dioxide; D014978:Xenon; D010424:Pentobarbital