Ifenprodil and SL 82.0715 potently inhibit binding of [3H](+)-3-PPP to sigma binding sites in rat brain.

SL 82.0715 and ifenprodil are potent anti-ischemic agents, which are believed to be due to non-competitive antagonism of N-methyl-D-aspartate (NMDA). It has been proposed that SL 82.0715 and ifenprodil non-competitively antagonize the actions of NMDA by interacting as antagonists with a polyamine site associated with the NMDA/phencyclidine (PCP)/glycine complex. The present study demonstrates that the actions of SL 82.0715 and ifenprodil may also be due in part to an interaction with sigma binding sites, a property that is not shared with polyamines.