Chronic Ethanol Exposure and Withdrawal Impair Synaptic GABAA Receptor-Mediated Neurotransmission in Deep-Layer Prefrontal Cortex

© 2019 by the Research Society on Alcoholism..

BACKGROUND: The prefrontal cortex (PFC) acts as an integrative hub for the processing of cortical and subcortical input into meaningful efferent signaling, permitting complex associative behaviors. PFC dysfunction is consistently observed with ethanol (EtOH) dependence and is a core component of the pathology of alcohol use disorders in current models of addiction. While intracortical gamma-aminobutryric acid (GABA)ergic neurotransmission is understood to be essential for maintaining coordinated network activity within the cortex, relatively little is known regarding functional GABAergic adaptations in PFC during EtOH dependence.

METHODS: In the present study, male and female (> postnatal day 60) Sprague-Dawley rats were administered EtOH (5.0 g/kg; intragastric gavage) for 14 to 15 consecutive days. Twenty-four hours after the final administration, animals were sacrificed and brains extracted for electrophysiological recordings of isolated GABAA receptor-mediated currents or analysis of GABAA receptor subunit protein expression in deep-layer PFC neurons.

RESULTS: Chronic EtOH exposure significantly attenuated activity-dependent spontaneous GABAA receptor-mediated inhibitory postsynaptic current (IPSC) frequency with no effect on amplitude. Furthermore, analysis of IPSC decay kinetics revealed a significant enhancement of IPSC decay time that was associated with decrements in expression of the α1 GABAA receptor subunit, indicative of further impaired phasic inhibition. These phenomena occurred irrespective of neuron projection destination and sex. Based on previous observations by our laboratory of an epigenetic mechanism for EtOH-induced changes in cortical GABAA receptor subunit expression, the histone deacetylase inhibitor Trichostatin A was administered to water- and EtOH-exposed animals, and prevented EtOH-induced changes in spontaneous IPSC frequency, IPSC decay kinetics, and GABAA receptor subunit expression.

CONCLUSIONS: Taken together, these results demonstrate that chronic EtOH exposure impairs synaptic inhibitory neurotransmission in deep-layer pyramidal neurons of the medial PFC in both male and female rats. These maladaptations occur in neurons projecting to numerous regions implicated in the sequelae of EtOH dependence, offering a mechanistic link between the manifestation of PFC dysfunction and negative affective states observed with extended consumption.

Medienart:

E-Artikel

Erscheinungsjahr:

2019

Erschienen:

2019

Enthalten in:

Zur Gesamtaufnahme - volume:43

Enthalten in:

Alcoholism, clinical and experimental research - 43(2019), 5 vom: 01. Mai, Seite 822-832

Sprache:

Englisch

Beteiligte Personen:

Hughes, Benjamin A [VerfasserIn]
Bohnsack, John Peyton [VerfasserIn]
O'Buckley, Todd K [VerfasserIn]
Herman, Melissa A [VerfasserIn]
Morrow, A Leslie [VerfasserIn]

Links:

Volltext

Themen:

3K9958V90M
Alcohol Dependence
Ethanol
Journal Article
Prelimbic mPFC
Receptors, GABA-A
Research Support, N.I.H., Extramural
Slice Electrophysiology

Anmerkungen:

Date Completed 02.07.2020

Date Revised 02.07.2020

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1111/acer.14015

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM294840125