Cyclical carotid artery flow reduction in conscious dogs: effect of a new thromboxane receptor antagonist.
Under sterile conditions, dogs were instrumented for continuous measurement of hemodynamics, and an Ameroid constrictor was positioned around the left carotid artery to produce slowly progressive narrowing of the vessel. In the awake, unsedated state, carotid cyclical blood flow reduction abruptly appeared on day 5.1 +/- 0.6 (mean +/- S.E.M.) at a frequency of 6.7 +/- 0.6 cycles per 30 minutes and usually remained present for only 1 day. The vessel was totally occluded on day 7.9 +/- 0.8. No focal neurologic deficit was observed. Following administration of the new thromboxane receptor antagonist, BM 13.505 (4-[2-(4-chlorobenzene-sulfonamide)-ethy]-benzene acetic acid), 50 and 100 micrograms/kg intravenously, the cyclical reduction in carotid blood flow was abolished for 30 +/- 5 and 45 +/- 15 minutes, respectively. No changes in systemic hemodynamics were observed over the course of the experiment. It is concluded that slowly progressive constriction of the carotid artery may provide an in vivo model for the study of perfusion deficits present in transient ischemic attacks. In addition, the results support the hypothesis that platelet aggregation plays a major role in cyclical carotid flow reduction, and the phenomenon can be eliminated by treatment with a new thromboxane receptor antagonist, BM 13.505.
al-Wathiqui
M H
MH
Department of Medicine, Medical College of Wisconsin, Milwaukee 53226.
Hartman
J C
JC
Brooks
H L
HL
Gross
G J
GJ
Warltier
D C
DC
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000188:drug therapy / Q000503:physiopathology*; D001783:Blood Flow Velocity; D002340:Carotid Artery Diseases / Q000188:drug therapy / Q000503:physiopathology*; D003243:Consciousness; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D010648:Phenylacetates / Q000627:therapeutic use*; D013449:Sulfonamides / Q000627:therapeutic use*; D013931:Thromboxanes / Q000037:antagonists & inhibitors*
D010648:Phenylacetates; D013449:Sulfonamides; D013931:Thromboxanes; C051762:daltroban