Neural control of bladder in the decerebrate, arterially‐perfused whole rat preparation (DAPRP)

Adapting the DAPRP (Pickering & Paton, 2006, 155(2); 260) we have produced a novel model for autonomic control of the bladder, which overcomes the need for anaesthesia and allows ease of access to pelvic structures. Bladder pressure, external urethral sphincter EMG (EUS) and pudendal nerve activity, recorded in the absence of muscle relaxant, showed characteristic features of coordinated rat micturition. For infusion‐evoked voids; bladder pressure, volume infused and voided were 32±7mmHg, 80±20μl and 25–90μl respectively (n=14). The rate of fluid infusion into the bladder (10–110μl/min) did not affect these parameters. Slow infusion caused greater non‐voiding spontaneous bladder contractions before the void, which appear to be distension related. Topical muscle relaxant (vecuronium; 2μg/ml) abolished the EUS response, as did ganglion blockade (hexamethonium; 300μM). Acute, sequential rostral‐caudal brainstem sectioning experiments showed that active voiding ceased when PAG and rostral pons was sectioned, although the filling response remained. Observation of robust eupnoeic phrenic activity, strong cardiorespiratory and nocifensive reflexes and co‐coordinated micturition indicates intact afferent‐efferent‐end‐organ connectivity in this model, which is suitable for evaluating central neural control of micturition in health and disease. This study was funded by Astellas.