Effects of dipyridamole on the cardiovascular response to +Gz stress in miniature swine.
Eight conscious female miniature swine experienced acceleration levels of 3, 5, and 7 +Gz before and after infusion of dipyridamole (1-2 mg.kg-1). Each animal was instrumented to measure ECG, heart level arterial pressure (AP), eye level arterial pressure (ELBP), left arterial pressure (LAP), heart rate (HR), and regional tissue blood flows. Each was also fitted with an abdominal anti-G suit which automatically inflated. Dipyridamole infusion had no direct effect on HR or LAP but AP was significantly reduced. All cardiovascular responses to +Gz were qualitatively similar before and after dipyridamole. Tachycardia always occurred. AP and CNS blood flow were maintained better prior to dipyridamole and AP always fell in proportion to acceleration intensity. +Gz was generally associated with increased blood flow to respiratory muscles and heart, decreased blood flow throughout the viscera and to the eyes. ELBP paralleled AP, but was always lower in direct proportion to the +Gz level. We conclude that dipyridamole reduces arterial pressure thus compromising the ability of the animal to sustain cerebral perfusion pressure (ELBP) during +Gz.
Peterson
D F
DF
Department of Physiology, Oral Roberts University Medical School, Tulsa, OK 74171.
Burns
J W
JW
Fanton
J W
JW
Laughlin
M H
MH
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000098:blood supply; D002302:Cardiac Output / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects* / Q000503:physiopathology; D004176:Dipyridamole / Q000008:administration & dosage / Q000494:pharmacology*; D005123:Eye / Q000098:blood supply; D006112:Gravitation; D005676:Gravity Suits; D006339:Heart Rate / Q000187:drug effects; D007262:Infusions, Intravenous; D013552:Swine; D013556:Swine, Miniature
D004176:Dipyridamole