First Advisor

Hugo Maynard

Term of Graduation

Summer 1977

Date of Publication

7-25-1977

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Psychology

Department

Psychology

Language

English

Subjects

Rats -- Behavior, Tetrahydrocannabinol

DOI

10.15760/etd.2537

Physical Description

1 online resource (3, 29 pages)

Abstract

This experiment was performed to determine whether a state-dependent learning effect is produced when rats are under the influence of Δ9 THC. A latent learning procedure utilizing a Lashley III maze was used. Latent learning paradigms offer one a variety of measures not available when using an operant procedure.

Forty-five female rats were run; five in each of nine conditions. Each set of nine rats was run as follows:

Days 1-5. Each rat received an injection of 0.0 mg/kg, 0.4 mg/kg, or 1.0 mg/kg of Δ9 THC. One-half hour later the rat received one-half hour of exposure in a Lashley III maze. The rats received the same doses for each of these five days.

Days 6-7. The rats were fed to maintain 80 percent ad lib weight.

Days 8-9. The rats received their test condition dosage of Δ9 THC (0.0 mg/kg, 0.4 mg/kg, or 1.0 mg/kg) and were then fed.

Day 10. The rats were injected with the test condition dosage and were then placed in the maze. Food was offered as reinforcement. Time-per-trial and errors-per-trial were recorded. One trial was run.

Day 11. The rats were given the test condition dose and placed in the maze for four reinforced trials.

The expectation was that a state-dependent learning effect would be evidenced by low scores in the 0.0 mg/kg-0.0 mg/kg, 0.4 mg/kg-0.4 mg/kg, and the 1.0 mg/kg-1.0 mg/kg conditions. This would result in a significant interaction effect when a three-way analysis of variance was performed on the data. This statistical effect did not happen.

An attempt was made to determine why the results were insignificant. The results did not replicate an earlier study done by Burke (personal communication). Burke obtained significant differences between the control group and the drug group. Doses ranged from 0.4 mg/kg to 2.0 mg/kg of Δ9 THC in the Burke experiment. Differences between the present study and the Burke study were explored. They were:

  1. Difference in sex of the rats.
  2. Ethanol in the solution used in the present study.
  3. This study used Δ9 THC and the Burke study used Marijuana Extract Distillate (MED).

It was concluded that the sex difference and the presence of ethanol were not factors that differentiated the present study from the Burke study. It was not clear whether MED is effective at lower doses than Δ9 THC. Literature on the synergistic effect of the components of marijuana other than Δ9 THC was conflicting. What was clear was that the minimum dose of Δ9 THC needed to produce a discriminable effect on behavior is 1.3 mg/kg. The maximum dose in the present procedure was 1.0 mg/kg. The suggestion was made that the present study be re-run with higher dose levels.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Comments

If you are the rightful copyright holder of this dissertation or thesis and wish to have it removed from the Open Access Collection, please submit a request to pdxscholar@pdx.edu and include clear identification of the work, preferably with URL.

Persistent Identifier

https://archives.pdx.edu/ds/psu/16110

Download

Included in

Psychology Commons

Share

COinS