Anticholinergic Treatment Reverses Haloperidol-Induced Blockade of Self-Stimulation of Nucleus Accumbens no less than of Hypothalamus

Two pairs of electrodes were implanted respectively in the nucleus accumbens (a terminal area of mesolimbic dopaminergic pathways) and in the lateral hypo-thalamic medial forebrain bundle (containing nigrostriatal as well as mesolimbic fibres of passage). Self-stimulation rates through both pairs of electrodes showed a similar dose-dependent depression by haloperidol (0·07 to 0·67 mg/kg IP), and a similar degree of restoration by hyoscine (scopolamine) (0·3 to 1·5 mg/kg IP). This result reinforces recent concern that anticholinergic agents, given to control extrapyramidal side-effects, may counteract the mesolimbic action of anti-psychotic drugs and lessen their therapeutic effect.