Molecular evidence for the functional role of dopamine D3 receptor in the morphine-induced rewarding effect and hyperlocomotion.

ABSTRACT: The aim of the present study was to investigate the role of dopamine D(3) receptors in the rewarding effect and hyperlocomotion induced by a prototypical mu-opioid receptor agonist morphine using dopamine D(3) receptor knock-out mice. The mu-opioid receptor in the brain determined by the [tylosil-3,5-(3)H(N)]-[D-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin binding assay was not significantly changed by a deletion of the dopamine D(3) receptor gene. Furthermore, we found that no significant differences in G-protein activation by morphine in the limbic forebrain and lower midbrain were noted between the two genotypes. These results suggest that the function of the mu-opioid receptor itself was not affected by a deletion of the dopamine D(3) receptor gene. To ascertain the morphine-induced rewardin

SUBMITTER: Narita M 

PROVIDER: S-EPMC6741920 | biostudies-literature | 2003 Feb

REPOSITORIES: biostudies-literature