[Changes in the resistance and capacity of the cerebral vascular bed under the influence of vasoactive substances].
Effects of intracarotid injections of vasoactive agents on cerebrovascular resistance (CVR) and cerebral blood volume (CBV) were studied in hemodynamically isolated brain of cats. Perfusion pressure shifts at a constant blood volume perfusion reflected CVR changes, and changes of venous outflow - CBV alterations. Administration of adrenaline, serotonin, and angiotensine was followed mainly by an increase of CVR  and a decrease of CBV. The CBR could be reduced by isopropilnoradrenaline, acetylcholine, histamine, and caffeine. CBV was decreased after isopropilnoradrenaline, acetycholine, histamine injections and increased by caffeine. The possible role of the active changes of cerebral capacitance vessels in the transcapillary fluid exchange is discussed. Capacitance vessels active responses are supposed to entail wrong results when using certain techniques for measurement of cerebral blood flow and metabolism.
D000109:Acetylcholine / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001810:Blood Volume / Q000187:drug effects*; D001921:Brain / Q000098:blood supply* / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects; D004837:Epinephrine / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D012701:Serotonin; D002110:Caffeine; D006632:Histamine; D000109:Acetylcholine; D009638:Norepinephrine; D004837:Epinephrine
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