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 microM and 300 microM) 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.