Do Presynaptic alpha-Adrenoceptors Exist in the Cardioaccelerator Nerve of Cold-blooded Animals? / 대한마취과학회지

1) The author investigated whether presynaptic alpha-adrenoceptors exist in the cardioaccelerator nerves of cold-blooded animals(frog, tortoise) as in ones of in mammals. 2) Each atrial preparation of a frog, tortoise and guinea-pig produced the positive chronotropic and inotropic responces to field stimulation. Each ventricular muscle preparation of frog and tortoise produced positive inotropic responces to field stimulation. 3) Both the responces of frog atrium and the inotropic response of frog ventrice to the stimulation were abolished or markedly inhibited by the presence of tetrodotoxin, guanethidine and proparanolo. Both responses of tortoise atrium to the stimulation were markedly inhibited by propranolol and the inotropic response ventricle to the stimulation was markedly inhibited by tetrodotoxin. 4) Both responses of frog and tortoise atrium, and the inotropic response of frog and tortoise ventricle to the stimulation were not affected by clonidine and yohimbine. 5) Both responses of guinea-pig atrium to the stimulation were markedly inhibited in the presence of clonidine and this clonidine-induced inhibition was not observed in the presence of yohimbine. 6) The above results suggest that presynaptic alpha-adrenoceptors do not exist in the cardioaccelerator nerves of frog and tortoise, being different from those of mammalisn animals.

The Effect of Propranolol on the Blood Pressure and Pulse Rate under Halothane Anesthesia / 대한마취과학회지

To combat the cardiovascular depression in blood pressure and palserate induced by halothane anesthesia in healthy persons after administration of propranolol(1.0mg) by the intravenous route, atropnie sulfate(0.5mg), ephedrine Hcl(20mg) and aramine(1.0mg) were administered respectively i.v. The results were as follows: 1) After i.v. administration of atropine sulfate, systolic blood pressure was elevated by 15 mmHg, diastolic blood pressure was elevated by 13mmHg, and pulse rate was increased by 24 per minute. 2) After i.v. administration of ephedrine, systolic blood pressure was elevated by 27 mmHg, diastolic blood pressure was elevated by 17mmHg, but significant pulse rate change was not observed. 3) After i.v. administration of aramine, systolic blood pressure was elevated by 29mmHg, diastolic blood pressure was elevated by 19mmHg, but pulse rate was decreased by 8 per minute. 4) As shown in the above results, in the cardiovascular depression due to halothane anesthesia after propranolol intravenous administration, blood pressure and pulse rated were corrected by treatment with atropine sulfate. Ephedrine and aramine effected elevation of the blood pressure, but not the pulse rate.