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 ≥ 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 BATPA. 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.