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 % N-2 + 5 % CO2 gassed bath solution. RESULTS: During anoxia, the open time constant (tau(2)), open probability (P-o) of 35-pS and 100-pS channels increased. Tet 7.5 mu mol.L-1 reduced the P-o of 35-pS and 100-pS channels, 15 and 30 mu mol.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.