Ethanol increases the firing rate of dopamine neurons of the rat ventral tegmental area in vitro.
The ventral tegmental area (VTA) is a brain region rich in dopamine-containing neurons. Since most agents which act as substrates for self-administration increase dopaminergic outflow in the mesolimbic or mesocortical areas, the VTA slice preparation may be useful for identifying drugs with potential for abuse. While ethanol (EtOH) is a drug of abuse which has been widely studied, the properties of ethanol which contribute to its abuse potential are not known. We have developed a brain slice preparation of the VTA in order to study the action of EtOH on putative dopamine neurons. Concentrations of EtOH from 20 to 320 mM produce a dose-dependent excitation of the dopamine-type neurons of the VTA. About 89% of neurons which have electrophysiological characteristics established for presumed dopamine-containing neurons were excited by ethanol in the pharmacologically relevant concentration range. This excitation persists in low-calcium, high-magnesium medium, which suggests a direct excitatory action of EtOH on dopamine-type cells in the VTA slice.
Brodie
M S
MS
Neuroscience Research, Abbott Laboratories, Abbott Park, IL 60064.
Shefner
S A
SA
Dunwiddie
T V
TV
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004298:Dopamine / Q000502:physiology*; D000431:Ethanol / Q000494:pharmacology*; D066298:In Vitro Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D013681:Tegmentum Mesencephali / Q000187:drug effects / Q000502:physiology*
D000431:Ethanol; D004298:Dopamine