Identification and validation of midbrain Kcnq4 regulation of heavy alcohol consumption in rodents

摘要

Currently available pharmacotherapies for treating alcohol use disorder (AUD) suffer from deleterious side effects and are not efficacious in diverse populations. Clinical and preclinical studies provide evidence that the Kcnq family of genes that encode K(v)7 channels influence alcohol intake and dependence. K(v)7 channels are a class of slowly activating voltage-dependent K+ channels that regulate neuronal excitability. Studies indicate that the K(v)7 channel positive modulator retigabine can decrease dopaminergic neuron firing, alter dopamine (DA) release, and reduce alcohol intake in heavy drinking rodents. Given the critical nature of ventral tegmental area (VTA) DA to the addiction process and predominant expression of Kcnq4 in DA neurons, we investigated the role of midbrain Kcnq genes and K(v)7 channels in the VTA of genetically diverse mice and long-term heavy drinking rats, respectively. Integrative bioinformatics analysis identified negative correlations between midbrain Kcnq4 expression and alcohol intake and seeking behaviors. Kcnq4 expression levels were also correlated with dopaminergic-related phenotypes in BXD strains, and Kcnq4 was present in support intervals for alcohol sensitivity and alcohol withdrawal severity QTLs in rodents. Pharmacological validation studies revealed that VTA K(v)7 channels regulate excessive alcohol intake in rats with a high-drinking phenotype. Administration of a novel and selective K(v)7.2/4 channel positive modulator also reduced alcohol drinking in rats. Together, these findings indicate that midbrain Kcnq4 expression regulates alcohol-related behaviors in genetically diverse mice and provide evidence that K(v)7.4 channels are a critical mediator of excessive alcohol drinking. (C) 2018 Elsevier Ltd. All rights reserved.