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THE LACK OF β‐ADRENOCEPTOR INVOLVEMENT IN THE CARDIAC ACTION OF Δ 1 ‐TETRAHYDROCANNABINOL IN RATS
Author(s) -
Li D. M. F.
Publication year - 1979
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1979.tb00727.x
Subject(s) - propranolol , hexamethonium , atropine , isoprenaline , δ9 tetrahydrocannabinol , chemistry , endocrinology , heart rate , medicine , tetrahydrocannabinol , increased heart rate , chronotropic , muscarinic acetylcholine receptor , pharmacology , receptor , cannabinoid , blood pressure , stimulation
SUMMARY 1. Rat isolated hearts perfused with Δ 1 ‐THC (0·5 μ/ml) showed a reduction in the rate of beating which was not altered by pretreatment with propranolol (2 μg/ml), atropine (4 μg/ml) or hexamethonium (4 μ/ml). 2. Propranolol (2 μg/ml) also caused a decrease in the rate of beating, which was not affected by pretreatment with Δ 1 ‐THC (0·5 μg/ml). 3. In pithed rats, propranolol (2 mg/kg, i.v.) caused a decrease in the pulse rate, which was not altered by prior administration of Δ 1 ‐THC (1 mg/kg, i.v.). 4. In both preparations, the responses to isoprenaline were markedly reduced or abolished by propranolol, but they were unaffected by Δ 1 ‐THC. 5. It is concluded that the hypotensive and cardiac slowing actions of Δ 1 ‐THC are not mediated by activation of parasympathetic nerves or by β‐adrenoceptor blockade.