A compartmentalized chamber for studying dopamine neurons in an hypothalamo-pituitary explant

An in vitro technique was developed which could be used to study whole neurons of the tuberohypophyseal dopaminergic (THDA) tract. Explants containing the medial basal hypothalamus (MBH; THDA cell bodies), pituitary stalk (THDA axons) and posterior pituitary (PP; THDA nerve terminals) were carefully dissected and placed in specially designed chambers. The chambers consist of separate compartments for the incubation of the MBH and PP while maintaining an intact pituitary stalk which traverses through a notched barrier. Dopamine (DA) synthesis in the explants was constant for 3 h and was significantly elevated by electrical stimulation. Electrical stimulation of both the PP and MBH increased endogenous DA release from the PP. DA release in response to potassium depolarization and dopaminergic drugs was significantly lower in explants than in the isolated PP even though spontaneous release was similar.

(1) this method is suitable for studying intact THDA neurons in vitro, and (2) intact THDA neurons respond differently to various stimuli than their excised terminals.