Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8351484 | Pharmacology Biochemistry and Behavior | 2014 | 10 Pages |
Abstract
This study examined whether chronic Î9-THC during early adulthood would produce the same hormonally-dependent deficits in learning that are produced by chronic Î9-THC during adolescence. To do this, either sham-operated (intact) or ovariectomized (OVX) female rats received daily saline or 5.6 mg/kg of Î9-THC i.p. for 40 days during early adulthood. Following chronic administration, and a drug-free period to train both a learning and performance task, acute dose-effect curves for Î9-THC (0.56-10 mg/kg) were established in each of the four groups (intact/saline, intact/THC, OVX/saline and OVX/THC). The dependent measures of responding under the learning and performance tasks were the overall response rate and the percentage of errors. Although the history of OVX and chronic Î9-THC in early adulthood did not significantly affect non-drug or baseline behavior under the tasks, acute administration of Î9-THC produced both rate-decreasing and error-increasing effects on learning and performance behavior, and these effects were dependent on their hormone condition. More specifically, both intact groups were more sensitive to the rate-decreasing and error-increasing effects of Î9-THC than the OVX groups irrespective of chronic Î9-THC administration, as there was no significant main effect of chronic treatment and no significant interaction between chronic treatment (saline or Î9-THC) and the dose of Î9-THC administered as an adult. Post mortem examination of 10 brain regions also indicated there were significant differences in agonist-stimulated GTPγS binding across brain regions, but no significant effects of chronic treatment and no significant interaction between the chronic treatment and cannabinoid signaling. Thus, acute Î9-THC produced hormonally-dependent effects on learning and performance behavior, but a period of chronic administration during early adulthood did not alter these effects significantly, which is contrary to what we and others have shown for chronic administration during adolescence.
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Authors
Peter J. Winsauer, Jessie L. Sutton,