ISSN:
1440-1681
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
SUMMARY 1. The effects of glucagon and l-isoprenaline on atrio-ventricular (A-V) conduction and sino-atrial (S-A) rate were studied in the isolated and cross-circulated canine A-V and S-A node preparations. Drugs were injected intravenously into the donor dog.2.l-Isoprenaline (0.01–3 nmol/kg) caused a dose-dependent decrease in the A-V conduction time and an increase in the S-A rate. In doses larger than 0.3 nmol/kg, a ventricular ectopic rhythm was provoked in the A-V node preparation. Dose-response curves for the changes in A-V conduction time and the S-A rate produced by l-isoprenaline were almost parallel and the responses were maximal with 3 nmol/ kg.3. Glucagon (0.03–3 nmol/kg) also caused a decrease in the A-V conduction time and an increase in the S-A rate in a dose-dependent manner, but unlike l-isoprenaline, it did not provoke a ventricular ectopic rhythm in the A-V node preparation even in large doses. The decrease in the A-V conduction time was maximal with 3 nmol/kg, whereas the increase in the S-A rate was not more than 50% of the maximum with this dose.4. The durations of the responses to glucagon were increased in a dose-dependent manner and were far longer than those to l-isoprenaline in equimolar doses. The positive chronotropic effect of glucagon was less than that of l-isoprenaline, not only in the S-A node preparation, but also in the donor dog.5. The findings suggest that glucagon may serve as a valuable agent in clinical medicine for decreasing A-V conduction time.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1440-1681.1974.tb00546.x
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