Fig. 6.

Effects of presession treatment with the σR antagonist, BD 1063, on responding maintained by (+)-pentazocine injection when substituted for cocaine. Each point represents the mean ± S.E.M. (n = 6). Ordinates are responses per second. Abscissae are the (+)-pentazocine injection dose in milligrams per kilogram (i.p.). Closed circles represent rates of responding maintained by (+)-pentazocine when vehicle was injected 5 minutes before the experimental session. Open symbols represent rates of responding maintained by cocaine when BD 1063 at doses specified in the key was injected 5 minutes before the experimental session.