Pharmacologic irreversible narrowing in chronic cerebrovasospasm in rabbits is associated with functional damage.
We studied isolated basilar artery segments from a rabbit model of chronic cerebrovasospasm. Autologous blood placed around the basilar artery of rabbits killed 1, 2, 3, 4, 5, 6, 7, or 9 days later caused narrowing of the segments with a biphasic time course. The first (immediate) phase was reversed by intra-arterial papaverine; the second phase exhibited an increasing component of narrowing that was papaverine-insensitive. Based on the passive force/length curves, basilar artery segments became increasingly stiff over 9 days. By contrast, the segments' contractility decreased. Responses of the basilar artery segments were greater over the first few days, but then became less than that of saline-injected controls. Contractions in response to norepinephrine and potassium were reduced. Endothelium-based acetylcholine-induced vasodilation progressively diminished, as did the response to sympathetic nerve stimulation. There was a negative correlation between artery wall stiffness and contractility. The papaverine-insensitive component of angiographic narrowing correlated directly with loss of contractility and with artery wall stiffness. These results are consistent with the conclusion that increased artery wall stiffness is a primary determining factor in the arterial narrowing of chronic cerebrovasospasm.
Vorkapic
P
P
Vermont Center for Vascular Research, University of Vermont, Burlington 05405.
Bevan
R D
RD
Bevan
J A
JA
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001488:Basilar Artery / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D002927:Cimetidine / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D002546:Ischemic Attack, Transient / Q000503:physiopathology*; D010208:Papaverine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology; D013345:Subarachnoid Hemorrhage / Q000503:physiopathology; D013779:Tetrodotoxin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects
D012701:Serotonin; D013779:Tetrodotoxin; D002927:Cimetidine; D006632:Histamine; D010208:Papaverine; D000109:Acetylcholine; D011224:Prazosin; D004837:Epinephrine