D-3 AND D-2 DOPAMINE-RECEPTORS - VISUALIZATION OF CELLULAR EXPRESSIONPATTERNS IN MOTOR AND LIMBIC STRUCTURES

The distribution of the D-3 and D-2 dopamine receptor subtypes in fore brain regions of the basal ganglia and mesocorticolimbic system was de termined. This was assessed through combined fluorescent visualization of subtype selective anti-peptide antibodies for these cloned recepto rs and detection of their ligand recognition sites using the D-2 subfa mily antagonist, N-(p-aminophenethyl) spiperone (NAPS fluoroprobe). Th e double-labeling technique enabled direct comparison of the cloned re ceptor proteins and NAPS fluoroprobe binding in vitro. The application of these two methods together produced results comparable to single-l abeling paradigms. Functional D-3 receptors, defined as the coincident fluorescence of the D-3 receptor antisera and fluoroprobe binding, we re detected in the core region of the nucleus accumbens and exhibited a laminated expression pattern in the frontal cortex. D-3 receptor pro tein was expressed robustly in neurons of the dorsolateral striatum, b ut showed an intense neuropil reaction in the globus pallidus. Functio nal D-2 receptors, defined as the coincident fluorescence of the D-2 r eceptor antisera and fluoroprobe binding, were detected in the frontal cortex and the medial shell of the nucleus accumbens. Thus, heterogen eities occurred in the cellular expression of functional D-3 and D-2 r eceptors in forebrain dopaminoceptive areas. D-3 appears more related to basal ganglia and structures involved with motoric behavior, while D-2 was associated with regions associated with cognitive/affective fu nctions. (C) 1995 Wiley-Liss, Inc.