ABSTRACT:The aim of this study was to explore the possibility of using rabbit bladder as a model for experimental detrusor electrostimulation research. In a study of urinary bladder activity induced through electrostimulation of the ventral roots, the functional and morphological parameters of the rabbit detrusor were investigated. Under general anaesthesia, open electrostimulation of ventral spinal roots leading towards the detrusor (usually S 2, S 3 ) was performed in 20 rabbits. Detrusor response was recorded by repeated electromyography and cystometry in two groups: animals with naturally concentrated urine content (Group A, eight rabbits) and animals after flushing and filling the bladder with saline (Group B, 12 rabbits). Histological examination of bladder wall was performed in both groups. The measured values were compared to one another as well as with data from the veterinary and human literature. The histological specimens were compared with histological specimens of human bladder. The reaction of detrusor fibres was detectable by electromyography in all cases. Elevation of intravesical pressure as a consequence of detrusor contraction was more difficult to detect, as this depends more on the density of the intravesical content. The pressure rise in Group B had a higher amplitude -up to 15 cm H 2 O versus 5 cm H 2 O in the first group (P = 0.00046). Histological examination of bladder wall from the two groups of rabbits showed no differences. In comparison with the bladder wall in humans, the only differences found were significantly thinner detrusor layers relative to the overall thickness of bladder wall. It is possible to use rabbit bladder for research into experimentally electrostimulation-induced activity of the detrusor or for experimental detrusor reinnervation research. It is necessary, however, to take into account certain limits -the lower contractility of the bladder wall and the need for qualitative control of bladder content. The present results also suggest that the physiological micturition of rabbits is probably more dependent on abdominal pressure than in humans. The lower urinary tract consists of the bladder and urethra. The shape, size and position of the bladder depend upon the amount of urine it contains. The bladder's volume increases several fold while filling. The histological structure of the bladder wall in rabbits and humans has been described as identical. Its external surface is mostly covered by the peritoneum. The bladder's muscle is divided into three layers with different fibre orientations: the external layer with a longitudinal arrangement, the middle layer with a circular arrangement, and the internal layer with a longitudinal arrangement. The internal surface consists of irregularly folded mucosa (Konig and Liebich 2005, Maxie 2008).

Background/Aims/Objectives: To verify the transfer of evoked potentials through anastomosis of an experimentally created micturition reflex arc and to detect said potentials directly on the detrusor and sphincter of rabbit urinary bladder. Methods: During 2013-2015, 17 rabbits were operated upon and measurement followed during reoperation 3-16 months later. Suitable ventral spinal roots were electrophysiologically detected following laminectomy, and a somatic-central nervous system-autonomic micturition reflex arc was created. During reoperation, the ventral root was stimulated above and below the anastomosis, the evoked potentials on the bladder detrusor and sphincter were measured, and intravesical pressure was monitored. Results: With stimulation above the anastomosis, 9 animals (53%) displayed a urinary bladder detrusor response and 7 (41%) a sphincter response. Four rabbits (24%) had elevated intravesical pressure. During the control stimulation below the anastomosis, we detected a detrusor response in 7 animals (41%), a sphincter response in 5 (29%), and elevated pressure in 4 (24%). Neither induction of micturition nor decrease in external sphincter activity occurred. Conclusions: Creation of a somatic-CNS-autonomic reflex arc is technically possible. However reflex activity transferring through the anastomosis is detectable on the detrusor only in some individuals, and is unable to induce a micturition reflex with or without accompanying detrusor-sphincter dyssynergia.

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