Effect of reperfusion on the cardiac acetylcholine and norepinephrine contents in rat hearts.
The effects of ischemia, reperfusion and hypoxia on the cardiac acetylcholine, choline, norepinephrine and cyclic AMP contents were investigated in isolated, spontaneously beating rat hearts perfused under constant pressure (100 cm H2O) with Krebs-Henseleit solution gassed with 95% O2-5% CO2. Acetylcholine, choline and norepinephrine were determined by high performance liquid chromatography with electrochemical detection. Cyclic AMP was determined by radioimmunoassay. One min reperfusion following 15 min ischemia (termination of perfusion) caused a significant decrease in both cardiac acetylcholine (P less than 0.05) and norepinephrine (P less than 0.01) contents, but had no significant effect on the cardiac norepinephrine/acetylcholine content ratio, or choline or cyclic AMP content. By contrast, 16 min ischemia did not significantly affect the cardiac acetylcholine, norepinephrine, choline or cyclic AMP content. Also, 16 min hypoxia (perfusion with Krebs Henseleit solution gassed with 95% N2 5% CO2) decreased the cardiac norepinephrine content significantly (P less than 0.01) and norepinephrine/acetylcholine content ratio slightly but not significantly. However, hypoxia had no significant effect on the cardiac acetylcholine, choline or cyclic AMP content. Pre-treatment with 10 microns atropine sulfate prevented the decrease in the cardiac acetylcholine content caused by reperfusion but caused a significant depletion in the cardiac norepinephrine content in the control (P less than 0.01) and ischemia (P less than 0.05) groups and a significant decrease in the norepinephrine/acetylcholine content ratio in all three groups (all, P less than 0.05). Extending the reperfusion period to 5 and 10 min following 15 min ischemia also caused a significant decrease in both cardiac acetylcholine and norepinephrine contents compared with the control groups. However, no significant difference in these contents was found between 1 min reperfusion group and 5 or 10 min reperfusion group. Twenty or 25 min ischemia alone did not significantly affect these contents. These findings suggest that reperfusion disturbs both the sympathetic and parasympathetic nervous systems in the heart and that pre-treatment with atropine adversely affects the balance of the autonomic nervous system.
Ohno
O
O
Second Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Tsuboi
H
H
Ogawa
K
K
Okumura
K
K
Ito
T
T
Hashimoto
H
H
Satake
T
T
D000109:Acetylcholine / Q000032:analysis*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D003326:Coronary Circulation; D000242:Cyclic AMP / Q000032:analysis; D006339:Heart Rate; D008297:Male; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000032:analysis*; D009638:Norepinephrine / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains
D001285:Atropine; D000242:Cyclic AMP; D000109:Acetylcholine; D009638:Norepinephrine