Pathophysiological investigation for characteristics of the mechanosensitive bladder afferent activities in relation with microcontractions in rats with storage dysfunction

2015 Fiscal Year Final Research Report

• Project/Area Number: 26861258
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Urology
• Research Institution: The University of Tokyo
• Principal Investigator: Aizawa Naoki 東京大学, 医学部附属病院, 特任助教 (80595257)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 求心性神経 / 膀胱 / 下部尿路閉塞 / ラット / 内因性カンナビノイド / 膀胱微小収縮

Outline of Final Research Achievements

We investigated the effect of several drugs on single-unit afferent activities (SAAs) of the bladder mechanosensitive primary afferent nerve fibers in rats. The study demonstrated that both α1A- and 1D adrenoceptors in the rat bladder are involved in the activation of the bladder Aδ-fibers during bladder filling. In addition, we demonstrated that enhanced peripheral endocannabinoids reduces C-fiber hyperactivity in the rat bladder provoked by PGE2.
We also evaluated the characteristics of mechanosensitive SAAs in the bladder in a male rat model of bladder outlet obstruction (BOO), and their relationship with microcontractions. The results indicate that the SAAs of Aδ-fibers were attenuated, but the SAAs of both Aδ- and C-fibers were intermittently enhanced by propagation of microcontractions during bladder filling in male rats with BOO. These findings support the view that microcontractions contribute to the development of urgency and/or detrusor overactivity associated with BOO.

Free Research Field

排尿生理・薬理学