[Abstract Title]. - Society for Neuroscience

Poster
257. Alcohol Intake and Preference
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 257.2/Z19
Topic: C.16.a. Alcohol
Support: AA13199
EB2092
Title: Influence of low dose oral ethanol on patterns of activity in cortico-mesolimbic system
related to responding for water
Authors: *D. J. WOODWARD, A. V. AZAROV;
Neurosci., Neurosci Resch Inst. North Carolina, Winston-Salem, NC
Abstract: The goal of this study was to describe activity patterns in cortico-mesolimbic neurons
during operant water intake to satiation when influenced by low doses of volitional oral ETOH.
Nucleus accumbens (NAC) and medial prefrontal cortex (mPFC) were implanted with arrays of
microwires. Neuron activity was recorded at 1 msec intervals during events defined by nose
pokes, tones and licks at a spout. Sprague Dawley rats water (W) deprived 24 hours responded
with an FR1 nose poke for 0.1 cc water during 15-hour sessions overlapping the dark phase of
normal lighting cycle. Food was provided ad lib in the light phase between the sessions and W -
for 24-48 hours after the session. Upon completion of the initial 64 FR1 W responses of the
session, ethanol was made available as a 15% v/v solution in tap water in a non-operant mode by
simple licking from an alternative spout, in the doses of 0.3, 0.4, 0.5 and 0.6 g/kg. Rapid (≤10
min/dose) ETOH intake was observed, which led in 10 to 30 min to interruption of W
responding. This interruption lasted from about 30 min at 0.3 g/kg dose and up to 5 hours at 0.6
g/kg. The estimated time to metabolize 0.6 g/kg ETOH in rat is about 1 hour. NAC and mPFC
neurons sustained unique activity patterns linked to nosepoke and CS tone events across the
initial 64 self-initiated FR1 water trials. These signals appeared in altered form within 30 min
upon the completion of ETOH intake. Later in the session with water responding resumed,
relative fading of those distinctly modified by ETOH neural response patterns was observed, but
not a restoration of the initial coding. This change of pattern has possibly resulted either from
developing satiation to water, fading of the pharmacological effects of the consumed ethanol,
and/or session global timing. This sequence of pattern transition shows that altered neural coding
of operant behavior by corticomesolimbic system (as in mPFC and NAC) is lasting over times
longer than required to metabolize a measured low dose of volitional oral ETOH. (AA13199 and
EB2092 to DJW)