Mapping of reinforcing and analgesic effects of the mu opioid agonist endomorphin-1 in the ventral midbrain of the rat.

ABSTRACT:

Introduction

Agonists at the mu opioid receptor (MOR) are widely recognized for their effects on reward and pain. Although prior studies have attributed some of these effects to MORs on GABA neurons in the ventral tegmental area (VTA), recent studies have identified a region of particularly strong MOR immunostaining residing caudal to the VTA, in a region denoted the rostromedial tegmental nucleus (RMTg).

Methods

Hence, we examined whether rats would self-administer small doses (50-250 pmol) of the selective MOR agonist endomorphin-1 (EM1) into the RMTg and adjacent sites. EM1 was chosen due to its short half-life, thus limiting drug spread, and due to its presence endogenously in brain neurons, including some afferents to the RMTg.

Results

The highest rates of EM1 se

SUBMITTER: Jhou TC 

PROVIDER: S-EPMC3482303 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature