Can neuroleptics influence the function of the brain hemispheres asymmetrically?

A long-term intracarotid tube was implanted in 32 rats. Intracarotid injection of 4 different neuroleptics (haloperidol, cis- and trans-flupenthixol, clopenthixol and reserpine) elicited a typical posture with abduction of the limbs on one side and and adduction on the other. Only the neuroleptically-active cis-isomers of flupenthixol and clopenthixol provoked this dystonic reaction. The posture spontaneously vanished after 24 hr and could be antagonized with the anticholinergic biperiden. Sham injections of Ringer's solution and isotonic glucose proved to be behaviourally inert. These results indicate an asymmetric distribution of the drugs in this experimental procedure. Their implications concerning drug-induced and spontaneous dystonias as well as psythopathology are discussed.