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EFFECTS OF Δ 9 ‐TETRAHYDROCANNABINOL ON THE RATES OF OXYGEN CONSUMPTION OF MICE
Author(s) -
PERTWEE R.G.,
TAVENDALE R.
Publication year - 1977
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1977.tb07535.x
Subject(s) - oxygen , hypothermia , chemistry , zoology , rectal temperature , tetrahydrocannabinol , δ9 tetrahydrocannabinol , endocrinology , anesthesia , medicine , biochemistry , biology , cannabinoid , receptor , organic chemistry
1 Experiments with untreated mice confirmed that at ambient temperatures below 30°C, the oxygen consumption rate of mice normally kept at about 23°C varies inversely with ambient temperature. 2 At given ambient temperatures in the range 20 to 31°C the oxygen consumption rate was 32 to 43% greater for restrained than for unrestrained mice. 3 Hypothermia induced in restrained mice by Δ 9 ‐tetrahydrocannabinol (Δ 9 ‐THC) (1.0 to 4.0 mg/kg i.v.) was accompanied by marked falls in the rate of oxygen consumption. The size of these falls parallelled the degree of hypothermia and increased both with increases in dose and with decreases in the ambient temperature. The oxygen consumption rates of unrestrained mice were also lowered by hypothermic doses (10 to 40 mg/kg i.p.) of Δ 9 ‐THC. 4 The maximum falls in oxygen consumption rate occurred at earlier times after drug administration than the maximum falls in rectal temperature. 5 At none of the ambient temperatures studied did the oxygen consumption rates of Δ 9 ‐THC‐treated mice fall significantly below the basal levels (59 ± 3 ml 25 g −1 h −1 ) of unrestrained, resting mice at 30°C. 6 The hypothesis that reduced rates of heat production contribute significantly towards the hypothermia induced by Δ 9 ‐THC in our experiments is discussed. The possibility that biological processes responsible for increased heat production in response to cold are more sensitive to Δ 9 ‐THC than those processes governing basal rates of heat production at thermally neutral environmental temperature is also raised.