Failure of anticholinergic drugs to antagonize the increase in dopamine seen after gammahydroxybutyric acid and axotomy.

The increase in dopamine (DA) seen either 30 or 90 min after injection of gammahydroxybutyric acid or 90 min after axotomy of the nigrostriatal DA-fibers was not affected by i.p. injections of either atropine sulfate or atropine methyl nitrate or benztropine. These increases in DA are most probably due to feedback-mechanisms which do not involve cholinergic neurons.