Inhibitory effect of standardized cannabis sativa extract and its ingredient cannabidiol on rat and human bladder contractility

OBJECTIVES: To evaluate the effect of a Cannabis sativa extract enriched in cannabidiol (CBD) botanic drug substance (BDS) and pure CBD, on bladder contractility in vitro. Cannabis based-medicines, including CBD-enriched extracts, have been shown to reduce urinary urgency, incontinence episodes, frequency, and nocturia in patients with multiple sclerosis.

METHODS: Strips were cut from male Wistar rats and the human bladder body and placed in organ baths containing Krebs solution. Contractions were induced by electrical field stimulation, acetylcholine, KCl, and α,β-methylene adenosine triphosphate.

RESULTS: CBD BDS significantly reduced the contractions induced by acetylcholine, but not those induced with electrical field stimulation, KCl, or α,β-methylene adenosine triphosphate in the isolated rat bladder. The inhibitory effect of CBD BDS was not significantly modified by the cannabinoid or opioid receptor antagonists or by modulators of calcium levels, but it was increased by ruthenium red and capsazepine, 2 transient receptor potential vanilloid type-1 blockers. In humans, CBD BDS and pure CBD significantly reduced acetylcholine-induced contractions, an effect that was not changed by the transient receptor potential vanilloid type-1 blockers.

CONCLUSIONS: Our data have suggested that CBD BDS reduces cholinergic-mediated contractility and that this effect is modulated by transient receptor potential vanilloid type-1 in rats but not in humans. CBD is the chemical ingredient of CBD BDS responsible for such activity. If confirmed in vivo, such results could provide a pharmacologic basis to explain, at least in part, the efficacy of Cannabis medicines in reducing incontinence episodes in patients with multiple sclerosis.