Inhibitory effect of 0,0-bisacetyldaurisoline on Ca2+ influx into synaptosomes

The inhibitory effects of 0,0-bisacetyldaurisoline (BDSL) on 45Ca2+ uptake and [3H]GABA release from synaptosomes were investigated. BDSL (1-100 mumol.L-1) produced a concentration-related inhibition of high K(+)-stimulated 45Ca2+ uptake and [3H]GABA release (IC50 = 5.6 +/- 0.7 and 31.4 +/- 2.3 mumol.L-1, respectively) in synaptosomes but verapamil (Ver) was only weakly active. Neither BDSL (100 mumol.L-1) nor Ver (100 mumol.L-1) modified 45Ca2+ uptake in control medium (K+ 5 mmol.L-1 resting uptake) and [3H]GABA release in Ca(2+)-free medium (K+ 45 mmol.L-1 basal release). The results suggest that BDSL may be a potent Ca2+ channel blocker in neurons.