The effect of endogenous cannabinoids on ischemia/reperfusion-induced arrhythmias

The endocannabinoid system is a neuromodulator and receptor system that affects neuronal synaptic communication in activities such as appetite, pain sensation, mood and memory. Cannabinoids are pharmacologically active molecules in diverse chemical structures. Cannabinoids are classified as an endocannabinoids, phytocannabinoids and synthetic cannabinoids. They reveal their effects by modulation of the cannabinoid receptors. There are mainly two type of receptors, cannabinoid 1(CB1) and cannabinoid 2 (CB2) in myocardial cells. We aimed to research the effect of endogenous cannabinoids on I/R-induced ventricular arrhythmias. 59 Wistar Albino rats were used in this project. Study have planned in 3 groups. Group I (n = 13) Control the solvent of the drugs DMSO at a dose of 1 ml/kg/i.v 10 min before ligation, Group II (n = 17) AM251 at dose of 1 mg/kg/i.v 10 min before ligation and Group III (n = 17) AM630 at 1 mg/kg/i.v dose 10 min before ligation. Ischemia will be produced by the ligation of the left main coronary artery for 6 min and reperfusion was produced by the release of the occluded coronary vessel for 10 min in anaesthetized rats. The CB1 antagonist AM251 significantly increased mortality, the incidence of ventricular tachycardia (VT) and ventricular fibrillation (VF), the duration of total arrhythmia with VF, and the arrhythmia scores in the reperfusion period compared to the control group. AM251 significantly increased the mean arterial blood pressure before the ligation. The CB2 antagonist AM630 did not cause a significant change the mortality rate and the incidence and duration of reperfusion arrhythmias. These results demonstrated that endogenous cannabinoids that occur in ischemia reperfusion period may suppress the generation of ventricular arrhythmias via the CB1 receptor activation.