AJP - Heart and Circulatory Physiology, Vol 256, Issue 5 1322-H1327, Copyright © 1989 by American Physiological Society
Chronic whole body sympathectomy fails to protect ischemic rabbit hearts
T. Matsuki, M. V. Cohen, G. Holt, J. Ayling, D. J. Hearse and J. M. Downey
Department of Physiology, College of Medicine, University of South Alabama, Mobile 36688.
We determined whether chronic chemical sympathetic denervation could
protect the rabbit heart against ischemia. Rabbits received 10 mg/kg
6-hydroxydopamine (6-HD) twice during the first week, then 100 mg.kg-1.wk-1
for the following 7 wk. After this interval the rabbits were anesthetized,
the chests were opened, and in each a coronary branch was occluded for 45
min followed by reperfusion for 3 h. Collateral flow was determined with
radioactive microspheres during coronary occlusion. Flow to the ischemic
myocardium of the 6-HD group (0.06 +/- 0.03 ml.min-1.g-1) was not
significantly different from that in the control group (0.04 +/- 0.02
ml.min-1.g-1). Infarct size was determined with triphenyltetrazolium
chloride staining. Average infarct size calculated as a percentage of risk
zone was similar in the 6-HD and control groups (59 +/- 15 and 60 +/- 12%,
respectively). We conclude that chronic chemical sympathectomy does not
induce collateral growth in the rabbit heart. Furthermore, endogenous
catecholamines do not contribute to injury in the ischemic rabbit heart.
