Δ9-tetrahydrocannabinol: Drug discrimination abuse liability testing in female Lister Hooded rats: Trials, tribulations and triumphs.
S S Rowton, B A Rocha, I E Porter
Journal of pharmacological and toxicological methods 2020 DOI: 10.1016/j.vascn.2020.106937 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Drug discrimination study Peer reviewed |
|---|---|
| Sample size | 10 |
| Population | Female Lister hooded rats |
| Interventions | Δ9-THC amphetamine morphine midazolam WIN55 212-2 CP-47 497 JWH-018 |
| Dose | 1.5 mg/kg IP for Δ9-THC training dose; 0.25, 0.75, 1.5, 3 mg/kg IP for Δ9-THC dose-response; 0.3 mg/kg SC amphetamine; 3 mg/kg IP morphine; 2.5 mg/kg PO midazolam; 0.75 to 2 mg/kg IP WIN55,212-2; 0.5 to 2 mg/kg IP CP-47,497; 1 mg/kg IP JWH-018 |
| Topics | Cannabis |
| Keywords | Cp-47.497 Cannabinoid Discrimination Jwh-018 Methods Rat Win55,212-2 δ9-THC |
| Key points | JWH-018 fully generalized to Δ9-THC, but WIN55,212-2 and CP-47,497 did not, raising questions about the reliability of drug discrimination for cannabinoid abuse potential assessment. |
Abstract
The assessment of the abuse potential of CNS-active drugs is a regulatory requirement. Drug discrimination is one of the nonclinical tests that contribute to this assessment by providing information on a drug's potential to induce a discriminative stimulus comparable to that of a known drug of abuse. The objective was to validate drug discrimination in the rat for the purpose of supporting regulatory submissions for novel drugs with potential cannabinoid-like activity. Ten female Lister hooded rats were trained to discriminate no-drug from Δ9-THC (1.5 mg/kg, IP) under a FR10 schedule of reinforcement. Once trained, a Δ9-THC dose-response curve was obtained using doses of 0.25, 0.75, 1.5, and 3 mg/kg, IP. This was followed by evaluation of amphetamine (0.3 mg/kg, SC); morphine (3 mg/kg, IP); midazolam (2.5 mg/kg, PO); and the synthetic cannabinoids WIN55,212-2 (0.75 to 2 mg/kg, IP), CP-47,497 (0.5 to 2 mg/kg, IP), and JWH-018 (1 mg/kg, IP) for their discriminative stimulus similarity to Δ9-THC. Pharmacological specificity was demonstrated by achieving the anticipated dose-response curve for Δ9-THC, and a vehicle-like response for the non-cannabinoid drugs. Although full generalisation was obtained for JWH-018, in contrast to published literature, WIN55,212-2 and CP-47,497 failed to generalise to Δ9-THC. Based on the literature review performed in light of the results obtained, contrasting and unpredictable behavioural responses produced by cannabinoids in animals and humans raises the question of the reliability and relevance of including drug discrimination and self-administration studies within an abuse potential assessment for novel cannabinoid-like drugs.
Comparable studies
Other preclinical and animal studies on cannabis, most cited first.
Citations in the library
Cited by 2
Cites 9
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