Distribution and Function of Cannabinoid Receptors 1 and 2 in the Rat, Monkey and Human Bladder

Abstract

The distribution of cannabinoid receptor 2 on sensory nerves and in the urothelium, and effects by CP55940 on the micturition interval and threshold pressure suggest a role for cannabinoid receptor 2 in bladder afferent signals. Co-expression of VAChT and cannabinoid receptor 2, and effects by CP55940 on nerve contractions suggest a cannabinoid receptor 2 mediated modulatory effect on cholinergic nerve activity. Anandamide may not be a good tool for cannabinoid receptor studies due to its activity at other receptors.

Cannabinoid receptor expression in the bladder is altered in detrusor overactivity

“…Gratzke et al [5] there was no immunoreactivity seen for CB1 on nerve structures using CRGP and VAChT antibodies but they did detect CB2 positive nerve fibres.…”

“…CB1 has been localised in the urothelium and nerve fibre structures of the suburothelium and detrusor [7][8][9]. In another study, CB1 receptors were not localised in the urothelium and nerve fibres, but CB2 immunoreactivity was found in these structures [5].…”

Cannabinoids and the Urinary Bladder

“…The mechanism of this effect is far from clear and published data on the expression and functional sites of cannabinoid receptors in the bladder are contradictory. It is thought that endocannabinoids bind to CB 1 and CB 2 , resulting in relaxation of the detrusor muscle during the filling phase [55,56]. CB 1 receptors are mainly found at the central and peripheral neuron terminals of the bladder, inhibiting neurotransmitter release [55].…”

“…It is thought that endocannabinoids bind to CB 1 and CB 2 , resulting in relaxation of the detrusor muscle during the filling phase [55,56]. CB 1 receptors are mainly found at the central and peripheral neuron terminals of the bladder, inhibiting neurotransmitter release [55]. Several studies have localized both cannabinoid receptors in the urinary bladder of humans rats mice and monkeys [2,[55][56][57][58][59][60].…”

“…CB 1 receptors are mainly found at the central and peripheral neuron terminals of the bladder, inhibiting neurotransmitter release [55]. Several studies have localized both cannabinoid receptors in the urinary bladder of humans rats mice and monkeys [2,[55][56][57][58][59][60]. The localization of CB 1 receptors has been described to be in the urothelium and nerve fibres of the suburothelium and in human and rat detrusor muscle [2,58,60].…”