Acute ethanol potentiates the clock-speed enhancing effects of nicotine on timing and temporal memory.
BACKGROUND
Acute ethanol administration potentiates some of the behavioral effects of nicotine, although the extent of this effect is unknown. The present investigation assessed the ability of ethanol to potentiate nicotine's effect on the overestimation of multisecond durations as a result of an increase in the speed of an internal clock.


METHODS
Adult male rats were exposed to the acute effects of ethanol (0.0, 0.5, 1.5, and 3.0 g/kg; IG) which was given 10 minutes prior to the administration of nicotine (0.0, 0.3, 0.6, and 1.0 mg/kg; IP). The effects of these combined treatments on timing and temporal memory were assessed using 18- and 36-second peak-interval procedures with separate visual/spatial cues for responding.


RESULTS
When administered alone, ethanol had no consistent effect on peak time, but decreased peak rate, and increased peak spread as a function of dose. In contrast, nicotine alone shifted the peak times of the response distributions leftward in a proportional manner as a function of dose. When administered after pretreatment with ethanol, nicotine's effect on the horizontal placement of the peak functions was potentiated.


CONCLUSIONS
The observation that ethanol pretreatment potentiates the clock-speed enhancing effects of subsequently administered nicotine is discussed in terms of the role of alpha7-nicotinic acetylcholine receptors and dopamine-glutamate interactions in cortico-striatal circuits thought to subserve interval timing.
Department of Psychology and Neuroscience, Duke University, Durham, North Carolina 27708, USA. meck@psych.duke.edu
Warren H
WH
Meck
D000435:Alcoholic Intoxication / Q000503:physiopathology*; D000818:Animals; D003463:Cues; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D011939:Mental Recall / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D009949:Orientation / Q000187:drug effects; D051381:Rats; D012055:Reinforcement Schedule; D013998:Time Perception / Q000187:drug effects / Q000502:physiology*; D014796:Visual Perception / Q000187:drug effects
D000431:Ethanol; D009538:Nicotine