NMDA receptor GluN2A subunit deletion protects against dependence-like ethanol drinking

Area of Science:

• Neuroscience
• Pharmacology
• Genetics

Background:

• N-methyl-D-aspartate receptors (NMDARs) mediate alcohol's behavioral and neurophysiological effects.
• The specific contribution of the GluN2A subunit to alcohol dependence is not well understood.

Purpose of the Study:

• To investigate the role of the GluN2A subunit in alcohol consumption and NMDAR function following chronic intermittent ethanol (CIE) exposure.
• To determine if GluN2A-containing NMDARs are involved in the development of alcohol dependence.

Main Methods:

• Mice with constitutive GluN2A gene knockout (KO) and wildtype littermates were exposed to chronic intermittent ethanol (CIE) vapor.
• Alcohol consumption and preference were assessed using a two-bottle choice paradigm.
• NMDAR-mediated synaptic transmission in the basolateral amygdala (BLA) was measured using ex vivo slice electrophysiology.

Main Results:

• GluN2A KO mice exhibited comparable blood alcohol levels to wildtypes after CIE but did not show increased alcohol drinking.
• CIE exposure did not alter BLA NMDAR-mediated synaptic transmission in GluN2A KO mice.
• Wildtype mice showed an attenuated synaptic response to GluN2B antagonism after CIE exposure.

Conclusions:

• GluN2A-containing NMDARs play a significant role in mediating increased alcohol consumption following repeated ethanol exposure.
• These findings suggest that GluN2A-containing NMDARs are a key mechanism underlying the risk for developing alcohol dependence.