Journal of Neuroscience, Vol 12, 970-975, Copyright © 1992 by Society for Neuroscience
Pentamidine is an N-methyl-D-aspartate receptor antagonist and is neuroprotective in vitro
IJ Reynolds and E Aizenman
Department of Pharmacology, University of Pittsburgh School of Medicine, Pennsylvania 15261.
Acquired immunodeficiency syndrome (AIDS) is frequently associated with
dementia. The wide spectrum of neurological abnormalities associated with
this dementia may involve a neurotoxin that activates the NMDA subtype of
glutamate receptor in neurons. We have found that the antimicrobial agent
pentamidine, which is prescribed for AIDS patients for the prophylaxis and
treatment of Pneumocystis carinii pneumonia, is an effective NMDA receptor
antagonist. Pentamidine inhibited 3H- dizocilpine binding to the NMDA
receptor in rat brain membranes at a site separate from glutamate, glycine,
and spermidine, with an affinity near 2 microM. Similar concentrations of
pentamidine block NMDA-induced increases in intracellular Ca2+ and
NMDA-induced currents in cultured forebrain and cortical neurons,
apparently without use dependence or voltage dependence, suggesting that
pentamidine may represent a novel chemical class of NMDA receptor
antagonist. Finally, pentamidine protects neurons from the lethal effects
of acute NMDA exposure in vitro. AS pentamidine may accumulate in the brain
at relevant concentrations following repeated high-dose parenteral
administration, these findings suggest that the drug may be neuroprotective
in vivo.