UMMS Affiliation

Department of Neurobiology; Emery Lab; Treistman Lab; Graduate School of Biomedical Sciences, Neuroscience Program

Date

7-23-2004

Document Type

Article

Subjects

Action Potentials; Animals; Calcium; Cell Compartmentation; Cell Line; Cells, Cultured; Dendrites; Electric Conductivity; Ethanol; Humans; Ion Channel Gating; Kinetics; Large-Conductance Calcium-Activated Potassium Channels; Male; Neurons; Nucleus Accumbens; Patch-Clamp Techniques; Potassium Channels, Calcium-Activated; Protein Subunits; RNA, Messenger; Rats; Rats, Sprague-Dawley

Disciplines

Neuroscience and Neurobiology

Abstract

Alcohol is an addictive drug that targets a variety of ion channels and receptors. To address whether the effects of alcohol are compartment specific (soma vs dendrite), we examined the effects of ethanol (EtOH) on large-conductance calcium-activated potassium channels (BK) in cell bodies and dendrites of freshly isolated neurons from the rat nucleus accumbens (NAcc), a region known to be critical for the development of addiction. Compartment-specific drug action was indeed observed. Clinically relevant concentrations of EtOH increased somatic but not dendritic BK channel open probability. Electrophysiological single-channel recordings and pharmacological analysis of the BK channel in excised patches from each region indicated a number of differences, suggestive of a compartment-specific expression of the beta4 subunit of the BK channel, that might explain the differential alcohol sensitivity. These parameters included activation kinetics, calcium dependency, and toxin blockade. Reverse transcription-PCR showed that both BK channel beta1 and beta4 subunit mRNAs are found in the NAcc, although the signal for beta1 is significantly weaker. Immunohistochemistry revealed that beta1 subunits were found in both soma and dendrites, whereas beta4 appeared restricted to the soma. These findings suggest that the beta4 subunit may confer EtOH sensitivity to somatic BK channels, whereas the absence of beta4 in the dendrite results in insensitivity to the drug. Consistent with this idea, acute EtOH potentiated alphabeta4 BK currents in transfected human embryonic kidney cells, whereas it failed to alter alphabeta1 BK channel-mediated currents. Finally, an EtOH concentration (50 mm) that increased BK channel open probability strongly decreased the duration of somatic-generated action potential in NAcc neurons.

Rights and Permissions

Citation: J Neurosci. 2004 Jul 21;24(29):6563-72. Link to article on publisher's site

DOI of Published Version

10.1523/JNEUROSCI.0684-04.2004

Comments

Co-author Paula L. Feinberg-Zadek is a student in the Neuroscience program in the Graduate School of Biomedical Sciences (GSBS) at UMass Medical School.

Related Resources

Link to Article in PubMed

Journal Title

The Journal of neuroscience : the official journal of the Society for Neuroscience

PubMed ID

15269268

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