Supersensitivity to GABA in the transmurally-stimulated vas deferens isolated from ethanol-dependent mice.

The effects of ethanol dependence on the sensitivity of the transmurally-stimulated mouse vas deferens to gamma-aminobutyric acid (GABA), noradrenaline and histamine were studied. Tissues isolated from ethanol-dependent mice showed supersensitivity to the twitch inhibitory effect GABA. Sensitivity to noradrenaline and histamine was not significantly altered. Exposure to ethanol in vitro significantly increased the sensitivity of the isolated mouse vas deferens to the inhibitory effect of histamine, noradrenaline and GABA. Pretreatment of vasa deferentia isolated from ethanol-dependent mice with bicuculline did not block the ethanol-induced supersensitivity to GABA, and naloxone was without effect on the supersensitivity to GABA observed in the transmurally-stimulated mouse vas deferens. It is concluded that ethanol dependence induces supersensitivity of the transmurally-stimulated mouse vas deferens to GABA, which is mediated by a bicuculline and naloxone-insensitive GABA receptor.