Experimental dissociation of hypothalamic functions: an analysis of neural structural components for prolactin...

A review of the research work done in male rats regarding the possible anatomical substrate underlying the control of prolactin release is presented. Also, a basis for the experimental dissociation of prolactin and LH release responses from a single brain locus is offered. It is proposed that the preoptic suprachiasmatic region (POA-Sch) encompasses neural elements involved in the facilitation and inhibition of prolactin release: the dorsal aspect of this region seems to encompass predominantly inhibitory neural elements for prolactin release, while more ventrally placed elements appear to be mostly facilitatory; inhibitory components of this hypothetical dual system for the control of pituitary prolactin release are significantly represented by incoming fibers coursing at some point as pericommissural, while facilitatory ones appear to be taking origin within the ventral half of the POA-Sch; and although direct stimulation of the ventral half of the POA-Sch often results in the combined release of prolactin and LH, it is possible to dissociate such responses by modifying the temporal structure of the applied electrical stimulus.