Ischemia alters cerebral vascular responses to hypercapnia and acetylcholine in piglets.
Effects of ischemia (20 min) on cerebral cortical prostanoid synthesis and microvascular responses to hypercapnia and topical acetylcholine were examined in anesthetized newborn pigs. Pial arteriolar dilation in response to hypercapnia (10% CO2 ventilation, 10 min) was absent 2 h after ischemia and reversed toward constriction by 24 h postischemia. In sham control piglets, hypercapnia increased cortical periarachnoid fluid prostanoid concentrations. After ischemia, hypercapnia did not affect prostanoid concentrations on the brain surface. Acetylcholine (10(-3) M)-induced pial arteriolar constriction was reversed toward dilation 24 h after cerebral ischemia. Further, acetylcholine-induced prostanoid synthesis was markedly attenuated after ischemia. We conclude that cerebral ischemia-reperfusion alters cerebral prostanoid synthesis and microvascular control in newborn pigs. These abnormalities persist for at least 24 h.
Leffler
C W
CW
Department of Physiology and Biophysics, University of Tennessee, Memphis 38163.
Busija
D W
DW
Armstead
W M
WM
Mirro
R
R
Beasley
D G
DG
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001921:Brain / Q000098:blood supply*; D002545:Brain Ischemia / Q000378:metabolism / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D015237:Dinoprost / Q000096:biosynthesis; D015232:Dinoprostone / Q000096:biosynthesis; D006935:Hypercapnia / Q000503:physiopathology*; D011453:Prostaglandins / Q000096:biosynthesis*; D013552:Swine; D013929:Thromboxane B2 / Q000096:biosynthesis*
D011453:Prostaglandins; D013929:Thromboxane B2; D015121:6-Ketoprostaglandin F1 alpha; D015237:Dinoprost; D015232:Dinoprostone; D000109:Acetylcholine