EFFECT OF 1, 1-DIPHENYL-3-PIPERIDINOBUTANOL HYDROCHLORIDE (ASPAMINOL) ON THE STIMULI-INDUCED CALCIUM UPTAKE IN RAT BRAIN SYNAPTOSOMES

Abstract

Effects of 1, 1-diphenyl-3-piperidinobutanol hydrochloride (Aspaminol), a nonspecific smooth muscle relaxant, on the uptake of calcium in the synaptosomes of rat brain were studied, using two stimuli i.e. high KCl and ATP. We also studied the effect of Aspaminol on the analgesic response of rat hindpaw using the Randall-Sellito test. The addition of Aspaminol inhibited the stimuli-induced calcium uptake in a concentration dependent manner. Aspaminol inhibited the high KCl induced calcium uptake competitively against the external calcium concentration. These findings suggest that Aspaminol may act on the surface of the synaptosomal membranes. In case of ATP stimulated calcium uptake, Aspaminol reduced the rate of uptake and maximal level of the synaptosomal calcium, and did not appear to have any effect on the rate of calcium release. These findings suggest that the inhibitory effect of Aspaminol can be mainly attributed to inhibition of the calcium influx, but not to acceleration of calcium efflux. In the five weeks old rats, Aspaminol did not influence the responses in the paw pinch test, but, in the weanling rats (about three weeks old), Aspaminol had a slight effect on the responses in the paw pinch test. This discrepancy may be due to difficulties in passing through the blood-brain barrier. Our findings suggest that a certain relationship may exist between the analgesic effect and the calcium uptake in the synaptosomes.