Role of GABA B receptors in the endomorphin-1-, but not endomorphin-2-, induced dopamine efflux in the nucleus accumbens of freely moving rats

European Journal of Pharmacology
Tadashi SaigusaA R Cools

Abstract

In vivo microdialysis was used to study the effects of the locally applied GABA B receptor antagonist 2-hydroxysaclofen and GABA B receptor agonist baclofen on the basal dopamine efflux as well as on the endomorphin-1- and endomorphin-2-induced dopamine efflux in the nucleus accumbens of freely moving rats. 2-Hydroxysaclofen (100 and 500 nmol) increased basal dopamine efflux. Baclofen (2.5 and 5 nmol) failed to affect basal dopamine efflux. 2-Hydroxysaclofen (1 and 10 nmol) which did not alter the basal dopamine efflux, enhanced the endomorphin-1 (25 nmol)-induced dopamine efflux. Baclofen (2.5 and 5 nmol) failed to affect endomorphin-1 (25 nmol)-induced dopamine efflux, but it counteracted the 2-hydroxysaclofen-induced increase of the endomorphin-1-elicited dopamine efflux. Neither 2-hydroxysaclofen (10 nmol) nor baclofen (5 nmol) affected the endomorphin-2 (25 nmol)-induced dopamine efflux. The doses mentioned are the total amount of drug over the infusion period that varied across the drugs (25 or 50 min). These results suggest that accumbal GABA B receptor plays an inhibitory role on the basal as well as the endomorphin-1-elicited accumbal dopamine efflux. The present results support our earlier reported notion that endomor...Continue Reading

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Citations

Sep 12, 2014·The European Journal of Neuroscience·Caitlin M Vander WeeleBrandon J Aragona
Nov 23, 2017·International Journal of Molecular Sciences·Magdalena Sustkova-FiserovaKamila Syslova
Nov 28, 2020·Cellular and Molecular Neurobiology·Cherkaouia KibalyCatherine M Cahill
Jan 1, 2021·International Journal of Molecular Sciences·Chrysostomos CharalambousMagdalena Sustkova-Fiserova
Oct 2, 2009·Peptides·Richard J Bodnar

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