Crop-Sac Response after Systemic and Intraventricular Administration of Neuroleptic Drugs

Abstract

Present experiments were aimed at studying, in pigeons, the effects of some neuroleptic agents given systemically or into the 3rd cerebral ventricle on PRL [prolactin] secretion and following morphological changes of the crop-sac mucosa both by classical histological methods and scanning electron microscopy. Such changes were also evaluated on the basis of a semiquantitative method using a 1-4 rating scale. Systemic treatment (3- or 5-day) with reserpine, haloperidol and (.+-.)-sulpiride produced an intense crop-sac response consisting of a marked epithelial hyperplasia and presence of milk-like material. Similarly, a much lower dose of haloperidol, clozapine and the 2 enantiomers of sulpiride given into the 3rd cerebral ventricle for 3 consecutive days produced a marked crop-sac response. The l-sulpiride was more active in comparison to the d-enantiomer. In pigeons, as in mammals, neuroleptic drugs are able to stimulate PRL secretion and these effects are mediated through an action at the hypothalamic and/or pituitary level by removing a tonic dopaminergic inhibition.