Effects of tetrandrine on changes of NMDA receptor channel in cortical neurons of rat induced by anoxia.

AIM To study the effects of tetrandrine (Tet) on the changes of NMDA receptor channels in cortical neurons induced by anoxia. METHODS Cell-attached configuration of patch-clamp techniques. Anoxia was produced by perfused cells with 95% N2 + 5% CO2 gassed bath solution. RESULTS During anoxia, the open time constant (tau 2), open probability (Po) of 35-pS and 100-pS channels increased. Tet 7.5 mumol.L-1 reduced the Po of 35-pS and 100-pS channels, 15 and 30 mumol.L-1 inhibited open of 100-pS channel fully, and changed the open time constant of 35-pS from two to single exponential distribution. CONCLUSION Tet inhibition of the open of NMDA receptor channels induced by anoxia was one of its protective mechanisms.