KCNK13 potassium channels in the ventral tegmental area of rats are important for excitation of VTA neurons by ethanol.

Background Alcohol excites neurons of the ventral tegmental area (VTA) and the release of dopamine from these neurons is a key event in ethanol reward and reinforcement. Many mechanisms for ethanol actions on neurons of the VTA have been proposed, but antagonists generally do not eliminate ethanol-induced excitation of VTA neurons. We have previously demonstrated that the ion channel KCNK13 plays an important role in ethanol excitation of mouse VTA neurons. Here, we elaborate on that finding and further assess the importance of KCNK13 in rats. Methods Rats (Sprague-Dawley and Fisher 344) were used in these studies. In addition to single unit electrophysiology in brain slices, we used quantitative PCR and immunohistochemistry to discern the effects of ethanol and the brain slice preparation method on the expression levels of Kcnk13 and KCNK13. Results Interestingly, immunohistochemistry demonstrated that the levels of KCNK13 were significantly reduced during procedures normally used to prepare brain slices for electrophysiology, such that there is a reduction of about 75% in KCNK13 protein at the time that electrophysiological recordings would normally be made. Extracellular recordings demonstrated that ethanol excitation of VTA neurons was reduced after knockdown of Kcnk13 using a small interfering RNA (siRNA) delivered via the recording micropipette. Real-time PCR demonstrated that expression of Kcnk13 was altered in a time-dependent manner after alcohol withdrawal. Conclusions KCNK13 plays an important role in ethanol stimulation of rat VTA neurons, and KCNK13 is dynamically regulated by cell damage, by ethanol exposure, and during withdrawal. KCNK13 is a novel alcohol-sensitive protein and further investigation of this channel may offer new avenues for the development of agents useful in altering the rewarding effect of alcohol.