Effect of topical nimodipine versus its ethanol-containing vehicle on cat pial arteries.
Nimodipine and its solvent containing ethanol were tested in a randomized in vivo study by local administration to the outer vessel wall surface of pial arteries and veins in 15 anesthetized cats. Reactions were studied through a cranial window. Diameter variations of 90 arterial and 78 venous vessel segments were continuously analyzed using a multichannel videoangiometer. The solvent alone caused minor though statistically significant (p less than 0.001) 7.6% dilatation, 8% in small and 7% in large arteries, which returned to their resting state after stopping treatment. 2.4 X 10(-5) M nimodipine plus solvent induced a 21% pial arterial dilatation (p less than 0.001), 26% in small and 17% in large arteries; dilatation induced by nimodipine plus solvent was significantly greater than dilatation by the solvent alone (p less than 0.001). After ceasing topical administration, arteries remained dilated by some 5%. Pial veins exhibited only minor reaction, i.e. a 6% (statistical n.s.) dilatation of large veins during nimodipine, and an 8% dilatation of small veins 20 minutes after stopping nimodipine. During solvent-administration rCBF, as estimated with the hydrogen clearance technique, remained unchanged. It is concluded that the dilatatory effect of the investigated compound on pial arteries is predominantly due to nimodipine.
D000287:Administration, Topical; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000098:blood supply; D002415:Cats; D002536:Cerebral Arteries / Q000187:drug effects*; D000431:Ethanol; D005260:Female; D008297:Male; D009539:Nicotinic Acids / Q000008:administration & dosage / Q000494:pharmacology*; D009553:Nimodipine; D012997:Solvents; D013997:Time Factors; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014680:Veins / Q000187:drug effects
D009539:Nicotinic Acids; D012997:Solvents; D000431:Ethanol; D009553:Nimodipine