| Abstrakt: |
Abstract Rationale: Because current findings indicate that the selectively bred alcohol-preferring P line of rats self-administers 50-200 mg% ethanol (EtOH) directly into the ventral tegmental area (VTA), whereas the alcohol-nonpreferring NP line does not, it is important to determine whether unselected, common stock rats would sell-administer EtOH directly into the VTA. In addition, because neuroanatomical and self-administration studies indicate that the VTA may be functionally heterogeneous, the present study was designed to determine whether there were subregional differences within the VTA for the intracranial self-administration (ICSA) of EtOH. Objectives: The objective of this study was to employ the ICSA technique to determine whether adult female Wistar rats would self-administer EtOH directly into the VTA, and whether regional heterogeneity existed for EtOH self-infusion within the VTA. Methods: Following surgery to implant guide cannulae aimed at either the posterior or anterior VTA, subjects were placed in standard experimental chambers equipped with an 'active lever' [fixed ratio (FR)1 schedule of reinforcement], which caused the delivery of the infusate, and an 'inactive lever', which had no programmed consequence. Subjects were assigned to groups that self-administered either artificial cerebrospinal fluid (aCSF) throughout, or 100-400 mg% EtOH for the first four sessions (acquisition), aCSF in sessions 5 and 6 (extinction), and EtOH again during session 7 (reinstatement). Results: During the four acquisition sessions, rats with posterior VTA placements readily self-administered 200 mg% and 250 mg% EtOH and discriminated between the active and inactive levers. These subjects also demonstrated extinction,... [ABSTRACT FROM AUTHOR] |
