As. Losavio et Ba. Kotsias, THE EFFECT OF AMINOPHYLLINE ON THE CONTRACTION THRESHOLD OF RAT DIAPHRAGM FIBERS AND ITS MODIFICATION BY 9-AMINOACRIDINE, Life sciences, 58(13), 1996, pp. 1031-1037
Citations number
17
Categorie Soggetti
Biology,"Medicine, Research & Experimental","Pharmacology & Pharmacy
We studied the effect of aminophylline (1 mM) and 9-aminoacridine (100
mu M) on the contraction threshold (CT) of rat diaphragm fibers (25 d
egrees C). The CT was measured by direct visualization (200 X) of the
fiber under current-clamp conditions. The main findings are the follow
ing: 1) Aminophylline lowers the CT toward more negative values of the
resting membrane potential (V-m). 2) 9-aminoacridine, a drug that dim
inishes Ca2+ release from the sarcoplasmic reticulum (SR), shifts the
CT toward more positive values; 3) this effect is overcome by aminophy
lline. We suggest that the displacement in the CT to more negative V-m
plays an important role in the potentiating effect of aminophylline.
This could be the result of an enhancement of Ca2+ release from the SR
.