The effect of β3-adrenoceptors agonist, mirabegron on the overactive bladder (OB) contractile activity regulation in female rats was studied. An experimental OB model was obtained by reserpine (Homviotensin) treatment of animals. Mirabegron (Betmiga) was administrated to animals with OB (M) for 2 weeks. Changes in the amplitude of neurogenic (electric field stimulated) and agonist-dependent contractile reactions of the bladder strips isolated from animals after medicines administration were determined.
It was found that the maximum level of neurogenic reactions of OB and M detrusor significantly exceeded the parameters of control animals. In the first case, the contractions were evoked by purinergic components and prostanoids, along with predominant cholinergic component. In the second case, the contraction amplitude increase of M strips is associated exclusively with the elevation of purinergic component activity and smooth muscles sensitivity to ATP. It should be noted that the level of detrusor M neurogenic reactions being stimulated with medium intensity was the same as in control. The management of OB with mirabegron in combination with other medicines requires further study.