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Antidepressant-like effect of venlafaxine is abolished in μ-opioid receptor-knockout mice

Soichiro Ide1, Shunsuke Fujiwara, Masayuki Fujiwara

  • 1Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Japan.

Journal of Pharmacological Sciences
|August 13, 2010
PubMed

Insights

Micro-opioid receptors are crucial for the antidepressant effects of venlafaxine, a common antidepressant. Venlafaxine

Area of Science:

  • Neuroscience
  • Pharmacology
  • Behavioral Science

Background:

  • The opioid system modulates depression-like behaviors.
  • The specific role of opioid receptors in antidepressant action remains unclear.

Purpose of the Study:

  • To investigate the role of micro-opioid receptors (MOPs) in the antidepressant-like effects of venlafaxine.
  • To determine if MOPs are necessary for venlafaxine's efficacy in reducing depression-like behaviors.

Main Methods:

  • Utilized MOP-knockout (KO) mice and wild-type (WT) littermates.
  • Administered venlafaxine, a serotonin and norepinephrine reuptake inhibitor.
  • Assessed antidepressant-like effects using the forced swim test.
  • Monitored locomotor activity to control for motor effects.

Main Results:

  • Venlafaxine significantly reduced immobility time in WT mice.
  • Venlafaxine failed to reduce immobility time in MOP-KO mice.
  • No significant differences in locomotor activity were observed between genotypes or treatment groups.

Conclusions:

  • Micro-opioid receptors play a critical role in mediating the antidepressant-like effects of venlafaxine.
  • Venlafaxine's efficacy in depression models is dependent on the presence and function of MOPs.
  • These findings highlight the involvement of the opioid system in antidepressant pharmacology.

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