Kv4.3 is a potassium channel that is involved in the repolarisation of action potentials in cardiac muscle. Kv4.3 is not a classic Cannabinoid receptor but its activity is modulated by cannabinoids. Since cannabinoids have a physiological effect on Kv4.3 it is effectively a Cannabinoid receptor.
Heart, brain (cortex, cerebellum, amygdala. caudate nucleus), smooth muscle, lower levels in the liver, skeletal muscle, kidney and pancreas.
Pertwee, R.G., Howlett, A.C., Abood, M.E., Alexander, S.P.H., Di Marzo, V., Elphick, M.R., Greasley, P.J., Hansen, H.S., Kunos, G., Mackie, K., et al. (2010). International Union of Basic and Clinical Pharmacology. LXXIX. Cannabinoid receptors and their ligands: beyond CB₁ and CB₂. Pharmacol. Rev. 62, 588–631.