Experimental neurogenic bladder disorder in non-human primates

These studies indicate that the monkey Macaca nemestrina provides a suitable model to evaluate the neurological mechanism of micturition. This animal has a sacral spinal center for micturition whereby the classification of primary patterns of neurogenic disorder into spinal reflex after suprasacral spinal cord section and autonomous after cauda equina section is validated. Attempts at dissociation of the spinal and vesical neurons by section of the cauda equina were characterized generally by raised rather than lowered tonus, irrespective of previous urinary diversion to prevent inadvertent overstretch of the bladder. No evidence was obtained to indicate that overstretch of the autonomous bladder is followed by loss of tonus but the survival times of the animals after cauda equina section were comparatively short. There was some indication that overstretch may induce coordinated contractility of the bladder when only the peripheral neuron and sympathetic innervation of the bladder are intact. Evidence was obtained that the monkey has a dual innervation of the mid urethra, in which the pressure profile is supported by alpha adrenergic receptors as well as some somatic neural control. The resting urethral pressure profile is preserved after low level section of the spinal cord or division of the cauda equina but is lower in amplitide after overstretch of the autonomous bladder.