A topographically organized gamma-aminobutyric acid projection from the ventral pallidum to the nucleus accumbens in the rat.
Anatomical and electrophysiological studies have indicated that a reciprocal projection from the ventral pallidum back to the nucleus accumbens exists and has functional relevance. In this study, the topographical projection from the ventral pallidum to the nucleus accumbens was examined by using retrograde tracing with fluoro-gold iontophoresed in subcompartments of the nucleus accumbens in rats combined with either in situ hybridization for glutamic acid decarboxylase and preproenkephalin mRNA or substance P immunoreactivity. Deposits made into the medial nucleus accumbens preferentially labeled neurons in the medial ventral pallidum, while deposits into the dorsolateral nucleus accumbens, at or lateral to the anterior commissure, labeled primarily cells in the dorsal and lateral ventral pallidum. A mediolateral to rostrocaudal topography was also observed, with the medial deposits preferentially labeling cells in rostral ventral pallidum and the lateral deposits resulting in retrogradely labeled cells in the ventral pallidum below the crossing of the posterior anterior commissure (subcommissural) as well as below the globus pallidus (sublenticular). The majority of cells retrogradely labeled with fluoro-gold were double-labeled for glutamic acid decarboxylase mRNA. In contrast, very few retrogradely labeled neurons in the ventral pallidum were double labeled for mRNA for preproenkephalin. These data demonstrate a topographically organized projection from the ventral pallidum to the nucleus accumbens that is primarily gamma-aminobutyric acid (GABA)-ergic and reciprocal to the GABAergic projection from the nucleus accumbens to the ventral pallidum.
Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University, Pullman 99164-6520.
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L
Churchill
P W
PW
Kalivas
D000818:Animals; D001931:Brain Mapping; D004745:Enkephalins / Q000235:genetics; D005456:Fluorescent Dyes; D005917:Globus Pallidus / Q000502:physiology*; D005968:Glutamate Decarboxylase / Q000235:genetics; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007478:Iontophoresis; D008297:Male; D009434:Neural Pathways / Q000737:chemistry / Q000502:physiology; D009714:Nucleus Accumbens / Q000502:physiology*; D011498:Protein Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D013266:Stilbamidines; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D004745:Enkephalins; D005456:Fluorescent Dyes; D011498:Protein Precursors; D012333:RNA, Messenger; D013266:Stilbamidines; D005680:gamma-Aminobutyric Acid; C033660:preproenkephalin; D005968:Glutamate Decarboxylase