Behavioral effects and binding affinities of two stereoisomeric psychotomimetic glycolates

A comparison was made of the behavioral effects in cats of the dextro and levo isomers of 3-quinuclidinyl benzilate (QB), using a special computer-controlled program. Such psychophysical parameters as rate of response and tendency to use the left or right paw for lever pressing were used primarily to evaluate drug efficacy. The drug did not alter auditory threshold or the percentage of errors in lever pressing. The l-isomer was found to be at least 100 times as potent as the d-isomer, the effects of both being qualitatively similar. After a single dose of 5 mug/Kg of 1-QB, the cats' performance did not return to normal until 5-7 days later. Pretreatment of the cats with a dose of 2 mg/Kg of atropine, an antimuscarinic agent, did not prevent the behavioral effects of 1-QB. The binding affinity of two isomers for synaptic membranes and phosphatidyl serine was identical.