Chronic whole body sympathectomy fails to protect ischemic rabbit hearts.
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.
Matsuki
T
T
Department of Physiology, College of Medicine, University of South Alabama, Mobile 36688.
Cohen
M V
MV
Holt
G
G
Ayling
J
J
Hearse
D J
DJ
Downey
J M
JM
D000818:Animals; D003097:Collateral Circulation; D003326:Coronary Circulation; D003327:Coronary Disease / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006352:Heart Ventricles; D006439:Hemodynamics / Q000187:drug effects; D006892:Hydroxydopamines; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology; D016627:Oxidopamine; D011817:Rabbits; D013563:Sympathectomy, Chemical; D014439:Tyramine / Q000494:pharmacology
D006892:Hydroxydopamines; D016627:Oxidopamine; D009638:Norepinephrine; D014439:Tyramine