title: Intravenous ethanol/cocaine self-administration initiates high intake of intravenous ethanol alone.
abstract: Evidence suggests that ethanol (EtOH) preexposure influences the rewarding valence of subsequent EtOH use. This study was conducted to determine if EtOH preexposure through EtOH/cocaine self-administration facilitates the motivational effects of EtOH alone. Rats self-administered intravenous (iv) EtOH/cocaine combinations (EtOH/Cocaine Fading group; EtOH 125.0 mg/kg/inj+Cocaine 0.1-0.75 mg/kg/inj) during a preexposure period. Consequently, these rats self-administered intravenous EtOH alone (62.5, 125.0, 250.0 and 500.0 mg/kg/inj) significantly more than a control group with prior cocaine self-administration experience (0.1-0.75 mg/kg/inj). In addition, at equal EtOH intake levels, locomotor activity was significantly enhanced in the EtOH/Cocaine Fading group but not the Cocaine Control animals (P=.01). The amount of EtOH self-administered in the EtOH/Cocaine Fading group during 1-h sessions (approximately 0.5-2.0 g/kg) corresponded with blood alcohol levels (BAL) ranging from 44 to 221 mg/dl. The highest BALs reported here have not previously been demonstrated after voluntary EtOH intake through any route of administration. These data suggest that preexposure to EtOH during EtOH/cocaine self-administration sessions modified neural substrates underlying both the reinforcing and locomotor responses to EtOH alone. Further studies utilizing intravenous EtOH self-administration will allow identification of various long-term behavioral and neural consequences of voluntary high EtOH intake.
authors.affiliation: College of Pharmacy, Division of Pharmacology/Toxicology, PHR 5.224, The University of Texas, Austin, TX 78712-1074, USA.
authors.forename: Aiko
authors.initials: A
authors.lastname: Ikegami
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Olsen
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Fleming
authors.forename: Erik E
authors.initials: EE
authors.lastname: Guerra
authors.forename: Michael A
authors.initials: MA
authors.lastname: Bittner
authors.forename: Jeremy
authors.initials: J
authors.lastname: Wagner
authors.forename: Christine L
authors.initials: CL
authors.lastname: Duvauchelle
mesh_terms: D000437:Alcoholism / Q000523:psychology*; D000818:Animals; D002492:Central Nervous System Depressants / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D002849:Chromatography, Gas; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology*; D019970:Cocaine-Related Disorders / Q000523:psychology*; D003216:Conditioning, Operant / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005502:Food; D008297:Male; D009042:Motivation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012646:Self Administration
chemical_list: D002492:Central Nervous System Depressants; D000431:Ethanol; D003042:Cocaine