Takeo Kohama

Effect of cerebellectomy on reflex micturition in the decerebrate dog as determined by urodynamic evaluation.

The effect of cerebellectomy on reflex micturition in the decerebrate dog was investigated by cystometric and striated urethral sphincter EMG studies. Before and after cerebellectomy, reflex micturition consisting of bladder contraction and spasmodic contraction of the striated urethral sphincter occurred when a critical degree of filling was reached. Cerebellectomy showed no influence on the striated urethral sphincter EMG activity. However, cerebellectomy produced a significant decrease in threshold volume and threshold pressure during the collecting phase, and also in the contraction pressure and voided volume of the emptying phase. The present study suggests that the cerebellum plays an inhibitory role in the collecting phase and a facilitatory role in the emptying phase during the entire reflex micturition cycle of the decerebrate dog. Further study will have to be done concerning the neurotransmission mechanism that causes these different effects in the collecting and emptying phases.

Neuroanatomical studies on pontine urine storage facilitatory areas in the cat brain. Part II. Output neuronal structures from the nucleus locus subcoeruleus and the nucleus reticularis pontis oralis

Input neuronal structures to the nucleus locus subcoeruleus (LSC) and the nucleus reticularis pontis oralis (PoO) were investigated by the horseradish peroxidase (HRP) study in cats. Under halothane anesthesia, a double barreled electrode was inserted into the LSC where electrical stimulation increased bladder capacity and the external urethral sphincter muscle activity, and into the PoO where chemical stimulation with carbachol increased bladder capacity and decreased the external urethral sphincter muscle activity. After identification of these regions, the HRP was ionphoretically injected into the LSC or PoO. By injecting the HRP into the LSC, retrogradely HRP labeled cells were located broadly in the frontal, rectal, orbitalis, rostral cingulate, internal aspect of posterior sigmoidal and anterior sylvian gyli, nucleus corticomedialis of amygdala, lateral area of the hypothalamus, paraventricular hypothalamic nucleus, substantia nigra, periaqueductal gray, reticular formation of the mesencephalon, pons and medulla, cerebellar nuclei and intermediate gray of the spinal cord. By injecting the HRP into the PoO, retrogradely HRP labeled cells were located broadly in the frontal, rectal, orbitalis, internal aspect of the posterior sigmoidal and anterior sylvian gyli, lateral area of the hypothalamus, paraventricular hypothalamic nucleus, periaqueductal gray, reticular formation of the mesencephalon, pons and medulla, cerebellar nuclei and intermediate gray of the spinal cord. These areas where HRP labeled cells were located mostly corresponded to the areas where electrical stimulation evoked either bladder relaxation or contraction in the previous reports. The LSC and the PoO seem to perform important roles in the neuronal mechanism for urine storage, receiving the inputs which facilitate or inhibit micturition from the extended areas between the cerebral cortex and the sacral spinal cord.

Role of the Pelvic Nerve in the Dynamics of Micturition in the Decerebrate Dog as Determined by Suprapubic Endoscopical and Urodynamic Evaluation

The role of the pelvic nerves on the dynamics of micturition was evaluated in 13 decerebrate dogs, four male and nine female, by direct observation of bladder movement, by suprapubic cystoscopic observation of urethral behavior, and by pressure flow EMG studies. Experiments were performed before and after unilateral pelvic nerve transection. In control conditions and after unilateral pelvic nerve transection, the bladder neck was not tightly closed during the collecting phase, the membranous portion of the urethra opened and closed spasmodically during the emptying phase, and reflex micturition developed. Direct observation showed that after unilateral pelvic nerve transection, the ipsilateral bladder did not contract. A pressure flow EMG study showed that unilateral pelvic nerve transection produced a significant increase in threshold volume, threshold pressure, bladder compliance and residual volume, and a significant decrease in contraction pressure and flow rate. The present study shows that unilateral pelvic nerve transection has no demonstrable effect on urethral function, but has effects on bladder function during the collecting and emptying phases and that bladder innervation is unilateral in the dog.