Shifting motivational states: The effects of nucleus accumbens dopamine and opioid receptor activation on a modified effort-based choice task.

Shifting motivational states: The effects of nucleus accumbens dopamine and opioid receptor activation on a modified effort-based choice task.
Behav Brain Res. 2020 Nov 05;:112999
Authors: Carlson HN, Murphy C, Pratt WE
Abstract
The nucleus accumbens (NAc) is critical for regulating the appetitive and consummatory phases of motivated behavior. These experiments examined the effects of dopamine and opioid receptor manipulations within the NAc during an effort-based choice task that allowed for simultaneous assessment of both phases of motivation. Male Sprague-Dawley rats received bilateral guide cannulas targeting the NAc core and were tested in 1-hr sessions with free access to rat chow and the choice to work for sugar pellets on a progressive ratio 2 (PR2) reinforcement schedule. Individual groups of rats were tested following stimulation or blockade of NAc D1-like or D2-like receptors, stimulation of µ-, δ-, or κ-opioid receptors, or antagonism of opioid receptors. Behavior was examined under ad libitum conditions and following 23-hr food restriction. NAc blockade of the D1-like receptors or stimulation of the D2 receptor reduced break point for earning sugar pellets; D2 receptor stimulation also modestly lowered chow intake. NAc µ-opioid receptor stimulation increased intake of the freely-available chow while simultaneously reducing break point for the sugar pellets. In non-restricted conditions, δ-opioid receptor stimulation...

Source: Behavioural Brain Research - November 5, 2020 Category: Neurology Authors: Carlson HN, Murphy C, Pratt WE Tags: Behav Brain Res Source Type: research