Mechanisms of D1/D2-like dopaminergic agonist, rotigotine, on lower urinary tract function in rat model of Parkinson’s disease

Parkinson’s disease (PD) is a neurodegenerative condition caused by the loss of dopaminergic neurons in the substantia nigra pars compacta. As activation of dopaminergic receptors is fundamentally involved in the micturition reflex in PD, the objective of this study was to determine the effect of a single dose of rotigotine ([−]2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin) on intercontraction interval (ICI) and voiding pressure (VP) in a rat model of PD. We used 27 female rats, PD was induced by injecting 6-hydroxydopamine (6-OHDA; 8 μg in 2 μL of 0.9% saline containing 0.3% ascorbic acid), and rotigotine was administrated at doses of 0.125, 0.25, or 0.5 mg/kg, either intravenous or subcutaneous injection. In rats with 6-OHDA-induced PD, intravenous injection of 0.25 or 0.5 mg/kg rotigotine led to a significantly lower ICI than after vehicle injection (p < 0.05). Additionally, VP was significantly lower in animals administered rotigotine compared to those injected with vehicle (p < 0.05). Compared to vehicle-injected animals, subcutaneous administration of rotigotine (0.125, 0.25, or 0.5 mg/kg) led to a significantly higher ICI at 2 h after injection (p < 0.05); however, there was no change in ICI after injection with (+)-SCH23390 hydrochloride. Dermal administration of rotigotine in a rat model of PD could suppress an overactive bladder.