Discriminative stimulus properties and brain distribution of phencyclidine in rats following administration by injection and smoke inhalation.
W D Wessinger, B R Martin, R L Balster
Pharmacology, biochemistry, and behavior October 1985 DOI: 10.1016/0091-3057(85)90425-3 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Animal discrimination study Peer reviewed |
|---|---|
| Sample size | 4 |
| Population | Male Sprague-Dawley rats |
| Intervention | Phencyclidine (PCP) |
| Dose | 3.0 mg/kg PCP (training dose); other PCP doses tested; THC doses up to those that markedly suppressed response rates |
| Key points | PCP administered by injection or smoke produced dose-dependent PCP-appropriate lever responding, while smoked delta 9-THC did not, even at doses that markedly suppressed response rates. Brain levels and distribution of 3H-PCP were roughly equivalent by both routes, which the authors say supports the validity of using injection when studying PCP experimentally. |
Abstract
Four male Sprague-Dawley rats were trained to discriminate IP injections of 3.0 mg/kg phencyclidine (PCP) from saline under a 2-lever fixed-ratio 32 schedule of food presentation. After reliable discriminative control of lever choice was established, other doses of injected PCP were tested resulting in dose-dependent increases in PCP-lever selection and dose-dependent decreases in rates of responding. When doses of PCP were administered by exposure to smoke from cigarettes containing PCP, a dose-dependent increase in PCP-lever responding was also observed. delta 9-Tetrahydrocannabinol administered via smoke exposure, up to doses which markedly suppressed response rates, did not result in PCP-appropriate responding, demonstrating the specificity of the PCP stimulus by the inhalation route. Brain levels and distribution of 3H-PCP were determined in rats administered doses calculated to result in 50% generalization by the IP injection or smoke inhalation routes. By both routes of administration roughly equivalent brain levels were attained and the distribution was relatively even across the seven brain areas analyzed. These results demonstrate the validity of using the injection route of administration when studying PCP experimentally, in spite of the fact that PCP is abused primarily by smoking.