Cerebrovascular effects of nimodipine in cats

The effects of nimodipine on feline pial arteries were studied before and after cortical spreading depression (CSD) using perivascular microapplication. Vessel diameter was measured by image splitting technique. Nimodipine was used as liposome suspension. Before CSD nimodipine induced a dilatation of 23.3 +/- 2.7% (mean +/- SEM) at 2.4 x 10(-7) M, while the empty liposomes elicited a nonsignificant constriction of 1.3%. After CSD the nimodipine-induced dilatation was significantly diminished to an average of 15%. This attenuated response to nimodipine is discussed and thought to be due to a more general decrease in cerebrovascular reactivity after CSD.