English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  The activation of GABA B  receptors in the ventral tegmental area (VTA) has been suggested to attenuate the rewarding properties of psychostimulants, including nicotine. However, the neurochemical mechanism that underlie this effect remains unknown. Since GABA B  receptors modulate the release of several neurotransmitters in the mammalian brain, we have characterised the effect of the GABA B  receptor agonist baclofen on the release of [ 3 H]-dopamine ([ 3 H]-DA) from VTA slices of naïve rats and of rats pre-treated with nicotine.    Results  In naïve rats, baclofen concentration-dependently inhibited the electrically evoked release of [ 3 H]-DA from the isolated VTA (EC 50  = 0.103 μM, 95% CI = 0.043–0.249), without affecting the basal [ 3 H]-monoamine overflow. This effect was mediated by activation of GABA B  receptors as it was blocked by the selective receptor antagonist CGP55845A. Chronic administration of nicotine (0.4 mg kg -1 , s.c., for 14 days) affected neither the basal nor the electrically evoked release of [ 3 H]-DA from VTA slices. However, the inhibitory effect of baclofen (10 μM) on the stimulated [ 3 H]-monoamine overflow was abolished in rats pre-treated with nicotine as compared to saline-injected controls.    Conclusions  Our results demonstrate that GABA B  receptor activation reduces the release of DA from the rat VTA. In addition, a reduced sensitivity of VTA GABA B  receptors appears to develop after chronic exposure to nicotine. The resulting disinhibition of VTA DA neurones might therefore contribute to the sensitised dopaminergic responses observed in the rat mesocorticolimbic system following repeated administration of nicotine.

bmc pharmacology

Reduced inhibitory action of a GABAB receptor agonist on [3H]-dopamine release from rat ventral tegmental area in vitro after chronic nicotine administration.