EFFECTS OF ETHANOL ON RAT SOMATOSENSORY CORTICAL-NEURONS

In this study, we characterized the local effects of ethanol (EtOH) on postsynaptic potentials (PSPs) and membrane properties of layer II-II I (L2-3) and layer V (L5) somatosensory cortical neurons. Intracellula r recordings were done using the in vitro slice preparation of rat som atosensory cortex. Our results show that EtOH exerts local effects on cortical cell membrane at physiologically relevant concentrations. A p redominant effect of EtOH was to reduce excitability of L2-3 and L5 ne urons by increasing the rheobase, decreasing input resistance and repe titive firing, reducing PSPs amplitude and the probability of evoking action potentials. Early (6 ms) and late (18 ms) PSP components were a ffected differentially by EtOH, the late components being more suppres sed. Overall, EtOH-mediated suppression of PSPs was stronger in L5 neu rons. Cortical neurons were divided into three subtypes: regular spiki ng adapting (RS-A), regular spiking non-adapting (RS-NA) and bursting (D-IB) neurons. PSPs evoked in RS-A neurons were more sensitive to EtO H suppressant effects. EtOH effects on input resistance were distribut ed differentially among the three groups of neurons. These results sup port the notion that EtOH disrupts higher processing of somatosensory information via a differential alteration of cortical neuron's membran e properties and synaptic transmission. (C) 1998 Elsevier Science B.V. All rights reserved.