Acamprosate inhibits Ca2+ influx mediated by NMDA receptors and voltage-sensitive Ca2+ channels in cultured rat mesencephalic neurones

Acamprosate has recently been introduced in relapse prophylaxis in weaned alcoholics. Using fura-2 microfluorimetry, the present study investigates whether acamprosate affects N-methyl-D-aspartate (NMDA) or K+-induced changes in free intracellular Ca2+ concentration ([Ca2+](i)) in rat cultured mesencephalic neurones. Both application of NMDA (plus glycine) and elevation of extracellular K+ induced rapid increases in [Ca2+](i) which respectively were insensitive and sensitive to omega -conotoxin (omega -CTX) MVIIC, a blocker of voltage-dependent Ca2+ channels (VDCCs). Acamprosate (100 muM and 300 muM) significantly attenuated the response induced by NMDA as well as that induced by K+ in a concentration-dependent manner. Concurrent application of omega -CTX MVIIC and acamprosate impaired the K+-induced increase in [Ca2+](i) to the same extent as omega -CTX MVIIC alone. The present data suggest that acamprosate inhibits Ca2+ influx through both NMDA receptors and VDCCs.