Effects of Gaba B Receptor Blockade on Lateral Habenula Glutamatergic Neuron Activity Following Morphine Injection in the Rat: An Electrophysiological Study Publisher

Summary: A study found blocking GABA receptors counters morphine's effects on brain activity, aiding addiction research. #BrainHealth #AddictionResearch

Amohashemi E¹ ; Alaei H¹ ; Reisi P¹
Source: Research in Pharmaceutical Sciences Published:2023

Abstract

Background and purpose: The lateral habenula (LHb), a key area in the regulation of the reward system, exerts a major influence on midbrain neurons. It has been shown that the gamma-aminobutyric acid (GABA)- ergic system plays the main role in morphine dependency. The role of GABA type B receptors (GABA B R s) in the regulation of LHb neural activity in response to morphine, remains unknown. In this study, the effect of GABA B R s blockade in response to morphine was assessed on the neuronal activity in the LHb. Experimental approach: The baseline firing rate was recorded for 15 min, then morphine (5 mg/kg; s.c) and phaclofen (0, 0.5, 1, and 2 μg/rat), a GABA B R s ' antagonist, were microinjected into the LHb. Their effects on firing LHb neurons were investigated using an extracellular single-unit recording in male rats. Findings/Results: The results revealed that morphine decreased neuronal activity, and GABA B R s blockade alone did not have any effect on the neuronal activity of the LHb. A low dose of the antagonist had no significant effect on neuronal firing rate, while blockade with doses of 1 and 2 μg/rat of the antagonist could significantly prevent the inhibitory effects of morphine on the LHb neuronal activity. Conclusion and implications: This result indicated that GABA B R s have a potential modulator effect, in response to morphine in the LHb. © 2023 Wolters Kluwer Medknow Publications. All rights reserved.