Dual actions of 5‐MeO‐DIPT at the serotonin transporter and serotonin 5‐HT1A receptor in the mouse striatum and prefrontal cortex

Abstract

Abstract Aims 5‐Methoxy‐N,N‐diisopropyltryptamine (5‐MeO‐DIPT) is a synthetic orally active hallucinogenic tryptamine analogue. The present study examined whether the effects of 5‐MeO‐DIPT involve the serotonin transporter (SERT) and serotonin 5‐hydroxytryptamine‐1A (5‐HT1A) receptor in the striatum and prefrontal cortex (PFC). Methods We investigated the effects of 5‐MeO‐DIPT on extracellular 5‐HT (5‐HTex) and dopamine (DAex) levels in the striatum and PFC in wildtype and SERT knockout (KO) mice using in vivo microdialysis, and for comparison the effects of the 5‐HT1A receptor antagonist WAY100635 and the 5‐HT1A receptor agonist 8‐OH‐DPAT on 5‐HTex. Results 5‐MeO‐DIPT decreased 5‐HTex levels in the striatum, but not PFC. In SERT‐KO mice, 5‐MeO‐DIPT did not affect 5‐HTex levels in the striatum or PFC. In the presence of WAY100635, 5‐MeO‐DIPT substantially increased 5‐HTex levels, suggesting that 5‐MeO‐DIPT acts on SERT and these effects are masked by its 5‐HT1A actions in the absence of WAY100635. 8‐OH‐DPAT decreased 5‐HTex levels in the striatum and PFC in wildtype mice. WAY100635 antagonized the 8‐OH‐DPAT‐induced decrease in 5‐HTex levels. In SERT‐KO mice, 8‐OH‐DPAT did not decrease 5‐HTex levels in the striatum and PFC. 5‐MeO‐DIPT dose‐dependently increased DAex levels in the PFC, but not striatum, in wildtype and SERT‐KO mice. The increase in DAex levels that was induced by 5‐MeO‐DIPT was not antagonized by WAY100635. Conclusion 5‐MeO‐DIPT influences both 5‐HTex and DAex levels in the striatum and PFC. 5‐MeO‐DIPT dually acts on SERT and 5‐HT1A receptors so that elevations in 5‐HTex levels produced by reuptake inhibition are limited by actions of the drug on 5‐HT1A receptors.

Keywords

• 5‐HT1A serotonin receptor
• 5‐MeO‐DIPT
• prefrontal cortex
• serotonin transporter
• striatum