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Regional heterogeneity for the intracranial self-administration of ethanol within the ventral tegmental area of female Wistar rats.
Psychopharmacology (Berl). 2000 Apr; 149(3):217-24.P

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 self-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, when aCSF was substituted for EtOH, and reinstatement when EtOH was reintroduced. Rats with posterior VTA placements self-infused 300 mg% and 400 mg% EtOH, and demonstrated lever discrimination only during the initial acquisition sessions. In contrast, rats with anterior VTA placements did not self-administer EtOH.

CONCLUSIONS

The findings suggest that EtOH is reinforcing within the posterior VTA of Wistar rats, and the VTA is a functionally heterogeneous structure with regard to EtOH reinforcement.

Authors+Show Affiliations

Department of Psychiatry, Institute of Psychiatric Research, Indiana School of Medicine, Indianapolis 46202-4887, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10823401

Citation

Rodd-Henricks, Z A., et al. "Regional Heterogeneity for the Intracranial Self-administration of Ethanol Within the Ventral Tegmental Area of Female Wistar Rats." Psychopharmacology, vol. 149, no. 3, 2000, pp. 217-24.
Rodd-Henricks ZA, McKinzie DL, Crile RS, et al. Regional heterogeneity for the intracranial self-administration of ethanol within the ventral tegmental area of female Wistar rats. Psychopharmacology (Berl). 2000;149(3):217-24.
Rodd-Henricks, Z. A., McKinzie, D. L., Crile, R. S., Murphy, J. M., & McBride, W. J. (2000). Regional heterogeneity for the intracranial self-administration of ethanol within the ventral tegmental area of female Wistar rats. Psychopharmacology, 149(3), 217-24.
Rodd-Henricks ZA, et al. Regional Heterogeneity for the Intracranial Self-administration of Ethanol Within the Ventral Tegmental Area of Female Wistar Rats. Psychopharmacology (Berl). 2000;149(3):217-24. PubMed PMID: 10823401.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Regional heterogeneity for the intracranial self-administration of ethanol within the ventral tegmental area of female Wistar rats. AU - Rodd-Henricks,Z A, AU - McKinzie,D L, AU - Crile,R S, AU - Murphy,J M, AU - McBride,W J, PY - 2000/5/24/pubmed PY - 2000/9/2/medline PY - 2000/5/24/entrez SP - 217 EP - 24 JF - Psychopharmacology JO - Psychopharmacology (Berl) VL - 149 IS - 3 N2 - 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 self-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, when aCSF was substituted for EtOH, and reinstatement when EtOH was reintroduced. Rats with posterior VTA placements self-infused 300 mg% and 400 mg% EtOH, and demonstrated lever discrimination only during the initial acquisition sessions. In contrast, rats with anterior VTA placements did not self-administer EtOH. CONCLUSIONS: The findings suggest that EtOH is reinforcing within the posterior VTA of Wistar rats, and the VTA is a functionally heterogeneous structure with regard to EtOH reinforcement. SN - 0033-3158 UR - https://www.unboundmedicine.com/medline/citation/10823401/Regional_heterogeneity_for_the_intracranial_self_administration_of_ethanol_within_the_ventral_tegmental_area_of_female_Wistar_rats_ L2 - https://dx.doi.org/10.1007/s002139900347 DB - PRIME DP - Unbound Medicine ER -