Effects of 3-quinuclidinyl benzilate on fixed-ratio responding and open field behavior in the rat

The effects of 3-quinuclidinyl benzilate (QNB) in the rat were evaluated on a fixed-ratio (FR) schedule of water reinforcement and on open field behavior in a novel environment. QNB had a biphasic effect on FR-20 responding: at a low dose (0.01 mg/kg SC) it increased, and at moderate to higher doses (0.05-1.0 mg/kg SC) it decreased bar pressing in a dose-dependent manner. The effect of QNB on the multiple indices of open field activity showed that at the low dose (0.01 mg/kg SC) it depressed spontaneous motor activity (SMA), while at higher doses (0.5 and 1.0 mg/kg SC) it enhanced SMA: rearing and forelimb flicks were unaffected at low doses and increased at higher doses. In general, QNB appears to produce differential effects on operant responding and open field activity.