- Low- and high-ethanol doses shifts the appetitive hedonic value of a natural reinforcer in infant rats: inflation and deflation effects.

CULLERÉ M; PAUTASSI, R.M.; PONCE LF; SPEAR NE; ABATE P; MOLINA JC

SAN DIEGO, EEUU

Congreso; 2009 Scientific Meeting of the Research Society on Alcoholism. RSA, EEUU; 2009

RESEARCH SOCIETY ON ALCOHOLISM

<!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 415 0;} @font-face {font-family:"Arial Narrow"; panose-1:2 11 6 6 2 2 2 3 2 4; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-pitch:variable; mso-font-signature:647 2048 0 0 159 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} p.MsoListBullet, li.MsoListBullet, div.MsoListBullet {mso-style-unhide:no; margin-top:0cm; margin-right:0cm; margin-bottom:0cm; margin-left:18.0pt; margin-bottom:.0001pt; text-indent:-18.0pt; mso-pagination:widow-orphan; mso-list:l0 level1 lfo1; tab-stops:list 18.0pt; font-size:12.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} /* List Definitions */ @list l0 {mso-list-id:-119; mso-list-type:simple; mso-list-template-ids:799965166;} @list l0:level1 {mso-level-number-format:bullet; mso-level-style-link:"Lista con viñetas"; mso-level-text:; mso-level-tab-stop:18.0pt; mso-level-number-position:left; margin-left:18.0pt; text-indent:-18.0pt; font-family:Symbol;} ol {margin-bottom:0cm;} ul {margin-bottom:0cm;} --> Reinforcing properties of ethanol are perceived early in life. Infant rats express appetitive and aversive ethanol-mediated learning. Appetitive effects are more easily observed at low doses (≤0.5 g/kg) and when the conditioning procedure is conducted during the early phase of the intoxication; while aversive effects seem prominent at higher doses (≥2.0 g/kg) and late during the course of the intoxication (Molina, Pautassi, Truxell and Spear, 2007). The interaction between ethanol’s unconditional properties and the hedonic attributes of natural rein forcers, however, has yet to be addressed. This study aimed at assessing if acute ethanol can shift (i.e., inflate) the motivational properties of a natural sapid reinforcer (sucrose). In Experiment 1, infant rats (postnatal days - PD - 14 to 15) were trained in an operant task where nose poke behavior was reinforced with an intraoral infusion of sucrose (10% w/v). Ethanol was administered immediately after each training session (0.0, 0.25, 0.5 or 1.5 g/kg). On PD 16 (test), animals that had been given 0.25 g/kg ethanol on PDs 14-15 exhibited more sucrose-reinforced operant behavior than control pups; while pups treated with 1.5 g/kg ethanol exhibited a significant decrease in responding for sucrose. In Experiment 2, pups were trained to nose poke (PD 14, 15 and 16) for sucrose (5% w/v,Exp 2A; 10% w/v, Exp 2B). At PD17 animals were briefly re-exposed to sucrose (4 infusions, 3 sec each, ISI 57 s) while experiencing the onset of an ethanol intoxication state (0.5 or 0.0 g/kg, US re-evaluation session). Operant responding for sucrose was then assessed. Pups given re-exposure to sucrose while intoxicated exhibited significantly more nose-poke responding than controls (Exp. 2B), a result that persisted even after withdrawing the reinforcer (i.e., extinction sessions, Exp. 2A and 2B) These results indicate that ethanol’s post-absorptive consequences can effectively shift (i.e., inflate or deflate) the reinforcing value of sucrose. The direction of this outcome seems to depend on appetitive and aversive attributes of the drug associated with low- and high-ethanol doses, respectively. These results are congruent with previous observations (Molina et al., 2006; 2007; Pautassi et al., 2006) indicating early ethanol-mediated reinforcement in the rat.