7-Oxo-Δ8-tetrahydrocannabinol as an active metabolite of Δ8-tetrahydrocannabinol

S. Narimatsu, T. Shimonishi, K. Watanabe

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Pharmacological effects of Δ8-tetrahydrocannabinol (THC) metabolites, 7α-hydroxy-Δ8-THC (7α-OH-Δ8-THC), 7β-OH-Δ8-THC and 7-oxo-Δ8-THC, were examined in mice using catalepsy, hypothermia and pentobarbital-induced sleep prolongation as indices. Each cannabinoid was injected to mice intravenously, and two doses of 5 and 10 mg/kg were used for assessments of hypothermia and barbiturates synergism. In cataleptogenic effect assessed using various doses, ED50 values of 7-oxo-Δ8-THC and 7α-OH-Δ8-THC were 3.2 and 7.5 mg/kg, respectively. The value of 7-oxo-Δ8-THC was comparable to that of Δ8-THC (3.3 mg/kg). In 7β-OH-Δ8-THC-treated groups, 25% of mice showed cataleptogenic effect at a dose of 13.8 mg/kg. In hypothermia, 7-oxo-Δ8-THC was most effective among three cannabinoids, and 7α-OH-Δ8-THC was the next. Pentobarbital (40 mg/kg, intraperitoneally)-induced sleep prolonging effect was also ranked in the following order, 7-oxo-Δ8-THC > 7α-OH-Δ8-THC > 7β-OH-Δ8-THC. The activity 7-oxo-Δ8-THC 7-oxo-Δ8-THc is comparable to that of Δ8-THC in all the pharmacological indices assessed. These results demonstrate that oxication at 7-position is one of the metabolically activating pathway of Δ8-THC.

Original languageEnglish
Pages (from-to)23-32
Number of pages10
JournalResearch Communications in Substances of Abuse
Issue number1
Publication statusPublished - Jan 1 1984

ASJC Scopus subject areas

  • Medicine (miscellaneous)


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