ISSN:
1432-1912
Keywords:
Supersensitivity
;
Diastolic potential
;
Perfused hearts
;
Isolated right atria
;
Norepinephrine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary It has previously been suggested that the reserpine-induced nonspecific increase in sensitivity of the guinea-pig heart to the chronotropic effect of drugs occurs as a result of an alteration in the electrophysiological properties of the cell membrane. The results obtained in the present study provide support for this suggestion. The diastolic potential of atrial cells of perfused hearts obtained from guinea pigs treated with reserpine (0.1 mg/kg/day) for 7 days was significantly less than control. This treatment schedule of reserpine results in a significant increase in the sensitivity of perfused hearts to the chronotropic effects of drugs. Treatment of animals with reserpine (0.1 mg/kg/day) for only 3 days does not increase the sensitivity of the perfused hearts and does not produce a significant change in the diastolic potential. Under appropriate experimental conditions, isolated spontaneously-beating right atria from chronically reserpine-treated guinea-pigs exhibit supersensitivity. Under the same conditions, there is a significant reduction in the membrane potential of atrial cells. Under conditions in which supersensitivity cannot be demonstrated in isolated right atria, there is no significant change in diastolic potential. These findings suggest that the reserpine-induced enhanced sensitivity of the myocardium to the rate-increasing effects of drugs may be a function of an altered membrane potential.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00498874
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