Bladder autonomic research has been impeded by the lack of whole animal models, which permit simultaneous investigation of central and peripheral neural activity during bladder filling and voiding. The aim of this study was to extend an established arterially perfused in situ decerebrate rat preparation [1] to characterise micturition by recording bladder pressure and external urinary sphincter (EUS) EMG. Female Wistar rats (40-80g) were anesthetized with 2-4% halothane. The bladder was accessed via a midline laparotomy. The stomach, spleen and intestine were tied and removed. The animal was immediately immersed in cold artificial CSF and decerebrated, at which point anaesthetic was withdrawn. The preparation was placed in a recording chamber and a double lumen cannula was inserted into the aorta. The preparation was perfused with carbogenated aCSF (32C). The heart resumed beating and rhythmic respiratory muscle contractions began within minutes, as perfusion pressure reached 40mmHg. A glass suction electrode recorded phrenic nerve activity. A cannula (i.d.200µm) was inserted into the ureter for filling (10µl/min saline). A 2nd cannula was inserted into the bladder for pressure monitoring. Midline dissection of the pubis symphysis revealed the EUS. A bipolar glass suction electrode (i.d.0.5mm) recorded EUS EMG. A camera microscope allowed synchronous monitoring of bladder contractions and times of fluid ejection from the urethra. This model produces viable preparations with robust eupnoeic phrenic activity indicative of an intact brainstem. Spontaneous bladder contractions (SBC) were seen in 23 (of 26) preparations. The mean frequency and amplitude of SBCs was 4.2±1.1/min and 3.8±2.0mmHg, respectively (n=10). Although the frequency of SBCs increased after fluid infusion to the bladder, they did not result in urination indicating intact EUS control. Bladder pressure recordings during infusion showed the characteristic rise in intraluminal pressure, followed by high frequency oscillations and a sharp decline, as described originally in rat [2]. In 4 preparations, EUS EMG comprised of strong bursting activity pre-ceeding each SBCs, suggestive of excitatory signalling to the EUS to maintain contraction and prevent leakage during SBCs (n=9). Application of ganglion blocker, hexamethonium (300µM), reduced EUS EMG, while the muscle relaxant, vecuronium bromide (2µg/ml), abolished it. Both agents resulted in leakage of urine associated with SBCs. The present decerebrate rat model has been successfully applied to study autonomic control of micturition. The technique overcomes restrictions present in vivo, such as need for anaesthesia, known to interfere with micturition. The technique can be extended to record activity from nerve bundles innervating the bladder and EUS and to study pathological models.