Chronic administration during early adulthood does not alter the hormonally-dependent disruptive effects of delta-9-tetrahydrocannabinol (Δ9-THC) on complex behavior in female rats.
Peter J Winsauer, Jessie L Sutton
Pharmacology, Biochemistry, and Behavior February 2014 DOI: 10.1016/j.pbb.2013.12.014 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Peer reviewed |
|---|---|
| Population | Female rats, either sham-operated (intact) or ovariectomized (OVX), in early adulthood |
| Dose | 5.6 mg/kg i.p. daily for 40 days (chronic); acute dose-effect curves 0.56–10 mg/kg |
| Duration | 40 days of chronic administration, followed by a drug-free period and acute dose-effect testing |
| Topics | Cannabis |
| Keywords | Behavior Learning Ovariectomy Rat Young adults ∆9-tetrahydrocannabinol |
| Key findings | Acute Δ(9)-THC produced rate-decreasing and error-increasing effects on learning and performance behavior that depended on hormone condition, with intact rats more sensitive than OVX rats. Chronic Δ(9)-THC during early adulthood did not significantly alter these acute effects or cannabinoid signaling, contrary to prior findings with adolescent administration. |
Abstract
This study examined whether chronic Δ(9)-THC during early adulthood would produce the same hormonally-dependent deficits in learning that are produced by chronic Δ(9)-THC during adolescence. To do this, either sham-operated (intact) or ovariectomized (OVX) female rats received daily saline or 5.6 mg/kg of Δ(9)-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 Δ(9)-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 Δ(9)-THC in early adulthood did not significantly affect non-drug or baseline behavior under the tasks, acute administration of Δ(9)-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 Δ(9)-THC than the OVX groups irrespective of chronic Δ(9)-THC administration, as there was no significant main effect of chronic treatment and no significant interaction between chronic treatment (saline or Δ(9)-THC) and the dose of Δ(9)-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 Δ(9)-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.
Comparable studies
Other preclinical and animal studies on cannabis, most cited first.
Citations in the library
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