Serotonin–GABA interactions modulate MDMA‐induced mesolimbic dopamine release
Michael G. Bankson, Bryan K. Yamamoto
Journal of Neurochemistry October 27, 2004 DOI: 10.1111/j.1471-4159.2004.02763.x via OpenAlex
Summary
AI-generated from the abstractMDMA (ecstasy) increases the release of the neurotransmitter GABA in the ventral tegmental area (VTA) of the rat brain, which in turn dampens the rise of dopamine in the nucleus accumbens (NAC) shell. This GABA increase depends on activation of serotonin 5-HT2B/2C receptors in the VTA, because blocking those receptors reduced the GABA rise and allowed dopamine in the NAC to increase more. By contrast, amphetamine also raised GABA in the VTA and dopamine in the NAC, but its GABA increase was not mediated by those serotonin receptors. The findings suggest a serotonergic braking mechanism that limits MDMA's dopamine-releasing effect.
Study at a glance
| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | Awake rats |
| Interventions | (+)‐MDMA d‐amphetamine SB 206553 TTX |
| Dose | 0, 2.5, 5 and 10 mg/kg MDMA; 5 mg/kg MDMA for 5-HT measurement; 4 mg/kg d-amphetamine |
| Topics | MDMA Serotonin |
| Keywords | Ventral tegmental area Microdialysis Nucleus accumbens Dopamine |
| Citations | 84 |
| Key finding | MDMA increases GABA efflux in the VTA via 5-HT2B/2C receptors, which dampens the concurrent increase in dopamine in the nucleus accumbens shell. |
Abstract
Abstract 3,4,‐Methylenedioxymethamphetamine (MDMA; ‘ecstasy’) acts at monoamine nerve terminals to alter the release and re‐uptake of dopamine and 5‐HT. The present study used microdialysis in awake rats to measure MDMA‐induced changes in extracellular GABA in the ventral tegmental area (VTA), simultaneous with measures of extracellular dopamine (DA) in the nucleus accumbens (NAC) shell. (+)‐MDMA (0, 2.5, 5 and 10 mg/kg, i.p.) increased GABA efflux in the VTA with a bell‐shaped dose–response. This increase was blocked by application of TTX through the VTA probe. MDMA (5 mg/kg) increased 5‐HT efflux in VTA by 1037% ( p < 0.05). The local perfusion of the 5‐HT 2B/2C antagonist SB 206553 into the VTA reduced VTA GABA efflux after MDMA from a maximum of 229% to a maximum of 126% of basal values ( p < 0.05), while having no effect on basal extracellular GABA concentrations. DA concentrations measured simultaneously in the NAC shell were increased from a maximum of 486% to 1320% ( p < 0.05). The selective DA releaser d‐amphetamine (AMPH) (4 mg/kg) also increased VTA GABA efflux (180%), did not alter 5‐HT and increased NAC DA (875%) ( p < 0.05), but the perfusion of SB 206553 into the VTA failed to alter these effects. These results suggest that MDMA‐mediated increases in DA within the NAC shell are dampened by increases in VTA GABA subsequent to activation of 5‐HT 2B/2C receptors in the VTA.