title: Adolescent but not adult rats exhibit ethanol-mediated appetitive second-order conditioning.
abstract: BACKGROUND
  Adolescent rats are less sensitive to the sedative effects of ethanol than older animals. They also seem to perceive the reinforcing properties of ethanol. However, unlike neonates or infants, ethanol-mediated appetitive behavior is yet to be clearly shown in adolescents. Appetitive ethanol reinforcement was assessed in adolescent (postnatal day 33, P33) and adult rats (P71) through second-order conditioning (SOC).
  
  
  METHODS
  On P32 or P70, animals were intragastrically administered ethanol (0.5 or 2.0 g/kg) paired with intra-oral pulses of sucrose (CS(1), first-order conditioning phase). CS(1) delivery took place either 5-20 (early pairing) or 30-45 minutes (late pairing) following ethanol administration. The time interval between CS(1) exposure and ethanol administration was 240 minutes in unpaired controls. On P33 or P71, animals were presented the CS(1) (second-order conditioning phase) in a distinctive chamber (CS(2), second-order conditioning). Then they were tested for CS(2) preference.
  
  
  RESULTS
  Early and late paired adolescents, but not adults, had greater preference for the CS(2) than controls, a result indicative of ontogenetic variation in ethanol-mediated reinforcement. During the CS(1)-CS(2) associative phase, paired adolescents given 2.0 g/kg ethanol wall-climbed more than controls. Blood and brain ethanol levels associated with the 0.5 and 2.0 g/kg doses at the onset of each conditioning phase did not differ substantially across age, with mean blood ethanol concentration of 38 and 112 mg%.
  
  
  CONCLUSIONS
  These data indicate age-related differences between adolescent and adult rats in terms of sensitivity to ethanol's motivational effects. Adolescents exhibited high sensitivity for ethanol's appetitive effects. These animals also showed ethanol-mediated behavioral activation during the SOC phase. The SOC preparation provides a valuable conditioning model for assessing ethanol's motivational effects across ontogeny.
authors.affiliation: Center for Developmental Psychobiology, Binghamton University, Binghamton, New York 13902-6000, USA. pautassi@binghamton.edu
authors.forename: Ricardo Marcos
authors.initials: RM
authors.lastname: Pautassi
authors.forename: Mallory
authors.initials: M
authors.lastname: Myers
authors.forename: Linda Patia
authors.initials: LP
authors.lastname: Spear
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Molina
authors.forename: Norman E
authors.initials: NE
authors.lastname: Spear
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects* / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D001921:Brain / Q000378:metabolism; D002492:Central Nervous System Depressants / Q000378:metabolism / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004435:Eating / Q000187:drug effects / Q000502:physiology; D000431:Ethanol / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology
chemical_list: D002492:Central Nervous System Depressants; D000431:Ethanol
references.citation: Alcohol Clin Exp Res. 2005 Jun;29(6):909-29
references.pmid: 15976517
references.citation: Behav Brain Res. 2007 Dec 3;184(2):109-16
references.pmid: 17675171
references.citation: Neurosci Biobehav Rev. 2000 Jun;24(4):417-63
references.pmid: 10817843
references.citation: J Stud Alcohol. 1997 May;58(3):280-90
references.pmid: 9130220
references.citation: Pharmacol Biochem Behav. 2002 Jun;72(3):659-68
references.pmid: 12175463
references.citation: Pharmacol Biochem Behav. 1999 May;63(1):131-6
references.pmid: 10340533
references.citation: Pharmacol Biochem Behav. 2008 Feb;88(4):393-402
references.pmid: 17936347
references.citation: Neuropharmacology. 2000 Jan 4;39(2):334-46
references.pmid: 10670429
references.citation: Alcohol. 2003 May;30(1):45-60
references.pmid: 12878274
references.citation: Dev Psychobiol. 2008 May;50(4):343-52
references.pmid: 18393275
references.citation: Pharmacol Biochem Behav. 1990 Feb;35(2):485-7
references.pmid: 2320661
references.citation: J Subst Abuse. 1997;9:103-10
references.pmid: 9494942
references.citation: Learn Mem. 2006 Sep-Oct;13(5):590-8
references.pmid: 17015856
references.citation: Alcohol Clin Exp Res. 2006 Sep;30(9):1506-19
references.pmid: 16930213
references.citation: Alcohol. 2000 Jan;20(1):45-53
references.pmid: 10680716
references.citation: Dev Psychobiol. 1983 Mar;16(2):83-109
references.pmid: 6339302
references.citation: Neurosci Biobehav Rev. 2004 Jan;27(8):721-8
references.pmid: 15019422
references.citation: Behav Brain Res. 2007 May 16;179(2):273-80
references.pmid: 17379324
references.citation: Dev Psychobiol. 1990 May;23(4):319-30
references.pmid: 2170214
references.citation: Recent Dev Alcohol. 2005;17:143-59
references.pmid: 15789864
references.citation: Ann N Y Acad Sci. 1992 Jun 28;654:506-8
references.pmid: 1632614
references.citation: Alcohol. 2005 Nov;37(3):167-72
references.pmid: 16713505
references.citation: Dev Psychobiol. 1981 Jul;14(4):327-32
references.pmid: 7250521
references.citation: Behav Neurosci. 2006 Oct;120(5):1115-32
references.pmid: 17014262
references.citation: Dev Psychobiol. 1997 Jan;30(1):29-39
references.pmid: 8989530
references.citation: Neurobiol Learn Mem. 2004 Jan;81(1):75-81
references.pmid: 14670361
references.citation: Alcohol. 1993 Mar-Apr;10(2):97-102
references.pmid: 8442898
references.citation: Dev Psychobiol. 1992 Dec;25(8):597-612
references.pmid: 1487084
references.citation: Alcohol Clin Exp Res. 2003 Apr;27(4):593-9
references.pmid: 12711921
references.citation: Pharmacol Biochem Behav. 1979 Jul;11(1):31-5
references.pmid: 493297
references.citation: Alcohol Clin Exp Res. 2001 Mar;25(3):391-402
references.pmid: 11290850
references.citation: Neurosci Biobehav Rev. 1995 Spring;19(1):133-41
references.pmid: 7770193
references.citation: Behav Neurosci. 1998 Oct;112(5):1152-66
references.pmid: 9829793
references.citation: Neurotoxicol Teratol. 2003 May-Jun;25(3):291-301
references.pmid: 12757826
references.citation: Behav Neural Biol. 1994 Nov;62(3):168-77
references.pmid: 7857239
references.citation: Pharmacol Biochem Behav. 2006 Jun;84(2):344-52
references.pmid: 16815539
references.citation: J Stud Alcohol. 1998 Jan;59(1):32-42
references.pmid: 9498313
references.citation: Dev Psychobiol. 2000 Jan;36(1):49-66
references.pmid: 10607361
references.citation: Alcohol Clin Exp Res. 2002 May;26(5):644-54
references.pmid: 12045472
references.citation: Int J Dev Neurosci. 2004 Aug-Oct;22(5-6):355-62
references.pmid: 15380835
references.citation: Am J Physiol. 1998 Jan;274(1):R248-54
references.pmid: 9458925
references.citation: Alcohol Clin Exp Res. 2006 Jun;30(6):1011-22
references.pmid: 16737460
references.citation: Alcohol. 2005 Jun;36(2):99-105
references.pmid: 16396743
references.citation: J Exp Psychol Anim Behav Process. 1991 Oct;17(4):433-47
references.pmid: 1744597
references.citation: Alcohol Clin Exp Res. 2004 Jun;28(6):884-94
references.pmid: 15201631
references.citation: Pharmacol Biochem Behav. 1992 Sep;43(1):307-13
references.pmid: 1409816
references.citation: Alcohol. 1988 Jul-Aug;5(4):309-13
references.pmid: 3228482
references.citation: Alcohol Clin Exp Res. 2006 Mar;30(3):448-59
references.pmid: 16499485
references.citation: Alcohol Clin Exp Res. 1998 Apr;22(2):416-21
references.pmid: 9581648
references.citation: Psychopharmacology (Berl). 1988;95(3):390-4
references.pmid: 3137627
references.citation: Alcohol. 2007 Feb;41(1):41-55
references.pmid: 17452298
references.citation: Physiol Behav. 1990 Jun;47(6):1279-81
references.pmid: 2395932
references.citation: Alcohol Clin Exp Res. 2000 Feb;24(2):232-7
references.pmid: 10698377