WSEAS Transactions on Biology and Biomedicine
Print ISSN: 1109-9518, E-ISSN: 2224-2902
Volume 22, 2025
The Acute Effects of Cannabis on Cardiac Arrhythmia and Myocardial Injury Induced by Epinephrine in the Rat
Authors: , , ,
Abstract: Cannabis, the most common illicit substance worldwide, has been associated with acute
cardiovascular events such as arrhythmia including premature ventricular contractions, ventricular tachycardia,
sinus arrest, and myocardial infarction. In this study, we investigated the effects of cannabis extract on
electrocardiographic parameters and cardiac histology in normal rats and in an epinephrine-induced arrhythmia
and myocardial damage anesthetized rat model. The possible modulation of cannabis effects by the nitric oxide
synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) was also examined. Male Sprague-Dawley rats
were treated with a single intraperitoneal (i.p.) dose of cannabis (equivalent to $$Δ^9$$-tetrahydrocannabinol content
of 20 mg/kg), prior to intravenous (i.v.) epinephrine (10 μg/kg) injection. In another group, cannabis (20 mg/kg,
i.p.) was administered prior to L-NAME (40 mg/kg, i.p.) and epinephrine (10 μg/kg, i.v.). The effects of
cannabis in normal rats were also investigated. The control group received saline. Results indicated that (i) the
administration of a single dose of cannabis at 20 mg/kg in normal rats slowed the heart rate by 12.3%, widened
the QRS complex by 110.5%, and caused a depressed ST segment, compared with the corresponding saline
control; (ii); cannabis given prior to i.v. epinephrine didn’t change the heart rate or QTc interval, but decreased
the PR interval by 23.2%, decreased QRS duration by 30%, increased R wave amplitude by 50%, induced
significant depression of the ST segment and wide QRS complex ventricular premature beats compared with
the corresponding epinephrine control group; (iii) cannabis significantly increased the number and duration of
epinephrine ventricular premature contractions and this showed further increase by pretreatment with LNAME.
Collectively, these results show that acute administration of cannabis in high doses caused slowing of
heart rate and ST changes in normal rats, suggestive of myocardial ischemia, and increased ventricular
arrhythmia induced by epinephrine. L-NAME increased ventricular arrhythmia caused by
cannabis/epinephrine.
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Keywords: cannabis, cardiac arrhythmia, epinephrine, myocardial injury, nitric oxide, nitric oxide synthase
Pages: 14-25
DOI: 10.37394/23208.2025.22.2