HIV-1 COAT PROTEIN GP120-INDUCED INCREASES IN LEVELS OF INTRASYNAPTOSOMAL CALCIUM

The effects of human immunodeficiency virus type-1 (HIV-1) coat protein gp120 on levels of intrasynaptosomal calcium ([Ca2+](i)) were determined in rat cortical synaptosomes. gp120 at concentrations of greater than or equal to 400 pM, significantly (P < 0.05) increased levels of [Ca2+](i). Treatment with 20 mM KCl, reduced the concentrations of gp120 necessary to produce significant (P < 0.001) increases in [Ca2+](i). gp120-evoked increases in [Ca2+](i) were prevented either by treatment with dantrolene or by removal of extracellular calcium with BAPTA. The peak levels of gp120-induced increases in [Ca2+](i) were not affected by calcium channel blockers lanthanum and nicardipine, by glutamate receptor antagonists MK-801 and NBQX, or by removal of endogenous glutamate with glutamate dehydrogenase. gp120-induced [Ca2+](i) increases in presynaptic terminals may play a role in HIV-mediated effects in the central nervous system.