Retention of cerebrovascular dilation after cortical spreading depression in anesthetized rabbits.
OBJECTIVE
We examined responses of rabbit pial arterioles to three different stimuli before and after induction of cortical spreading depression.


METHODS
In urethane-anesthetized rabbits equipped with a closed cranial window, we measured pial arteriolar diameter during baseline conditions, topical application of calcitonin gene-related peptide (CGRP), topical application of acetylcholine, and inhalation of 10% CO2 in air (arterial hypercapnia) before cortical spreading depression and 30, 60, and 120 minutes after cortical spreading depression. Cortical spreading depression was induced by localized application of a 5% KCl solution anterior to the arteriole being measured.


RESULTS
Average baseline diameter was approximately 90 microns. During cortical spreading depression, arteriolar diameter increased to a peak value that was 50 +/- 4% above baseline (n = 32). Before cortical spreading depression, arteriolar diameter changed 47 +/- 7% (n = 9) during hypercapnia, 17 +/- 3% (n = 4) during 10(-9) mol/L CGRP, 42 +/- 10% (n = 7) during 10(-7) mol/L CGRP, 29 +/- 6% (n = 4) during 10(-6) mol/L acetylcholine, and 61 +/- 13% (n = 6) during 10(-4) mol/L acetylcholine. Arteriolar responsiveness to any of these stimuli was not changed significantly by prior cortical spreading depression.


CONCLUSIONS
Dilator capacity of pial arterioles is still intact in urethane-anesthetized rabbits after cortical spreading depression.
Busija
D W
DW
Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Wake Forest University, NC 27157-1083.
Meng
W
W
D000109:Acetylcholine / Q000494:pharmacology; D000768:Anesthesia, General; D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000502:physiology*; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D002245:Carbon Dioxide / Q000494:pharmacology; D002560:Cerebrovascular Circulation; D013181:Cortical Spreading Depression; D005260:Female; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D010841:Pia Mater / Q000098:blood supply*; D011817:Rabbits; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects
D002245:Carbon Dioxide; D015740:Calcitonin Gene-Related Peptide; D000109:Acetylcholine