Join Copernicus Academic and get access to over 12 million papers authored by 7+ million academics.

Related Articles:

• The effect of Vitamin E on learning and memory deficits in intrahippocampal kainate-induced temporal Read more...

• Nongenomic actions of neurosteroid pregnenolone and its metabolites.

• Gonadal hormones affect alcohol drinking, but not cue+yohimbine-induced alcohol seeking, in male and Read more...

• Prenatal nicotine exposure induces depression‑like behavior in adolescent female rats via modulati Read more...

• Vitamin E attenuates nicotine- and noise-induced reproductive impairment in male albino Wistar rats.

NeuropharmacologyThe neurosteroid pregnenolone sulfate neutralized the learning impairment induced by intrahippocampal nicotine in alcohol-drinking rats

E. Martín-García - No affiliation found

2005/01/01 Full-length article DOI: 10.1016/j.neuroscience.2005.08.036 Journal: Neuroscience

Abstract:

AbstractThe effects of intrahippocampal administration of nicotine and the neurosteroids pregnenolone sulfate and allopregnanolone on acquiring the lever-press response and extinction in a Skinner box were examined using voluntary alcohol-drinking rats. A free-choice drinking procedure that implies early availability of the alcoholic solution (10% ethanol v/v+3% glucose w/v in distilled water) was used. Alcohol and control rats were deprived of food and assigned at random to six groups. Each group received two consecutive intrahippocampal (dorsal CA1) injections immediately after 1-h of drinking ethanol and before the free lever-press response shaping and extinction session. The groups were: saline–saline; saline–pregnenolone sulfate (5 ng, 24μM); saline–allopregnanolone (0.2μg, 1.26μM); nicotine (4.6μg, 20mM)–saline; nicotine–pregnenolone sulfate; nicotine–allopregnanolone. Blood alcohol concentrations were assessed the day before conditioning. The combination of the oral self-administration of ethanol and the intrahippocampal injection of nicotine deteriorated the ability to acquire the lever-press response. This effect was neutralized by intrahippocampal pregnenolone sulfate (negative modulator of the GABAA receptor complex), and it was not affected by intrahippocampal allopregnanolone (positive GABA receptor complex A modulator). Pregnenolone sulfate and allopregnanolone had no effects per se on lever-press acquisition, neither in alcohol-drinking rats nor in controls. Alcohol consumption facilitated operant extinction just as anxiolytics that act as positive modulators of the GABA receptor complex A receptors do, possibly reducing the anxiety or aversion related to non-reinforcement. This effect was increased by intrahippocampal nicotine.