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KMID : 0376219690060010089
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Chonnam Medical Journal
1969 Volume.6 No. 1 p.89 ~ p.103
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Central influence on micturition threshold and tonus limb of the cystometrograms in the unanesthetized rabbits
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Yin Byung-Sung
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Abstract
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It is a well established fact that the micturition reflexes occur as the spinal reflex controlled by the sacral centers through the afferents and effe rents innervating the bladder, however, physiological mechanism of the bladder to sustain tonus is not clearly understood. Sherrington, and Langworthy et. al. ascribed the origin of the bladder tonus to a reflex mechanism analogous to a stretch reflex of skeletal muscle, which is under the. influence of higher centers in the brain. This conception on the origin of the bladder tonus has been accepted by many investigators. Recently Tang and Ruch asserted non-neurogenic basis of the bladder tonus, which negates any roles of central nervous-system upon the bladder tonus.
In this work, applying the cystometry in the unanesthetized rabbits, micturition thresholds and pressures were measured in intact state, at the same. time, influences of the higher centers upon the micturition thresholds and bladder tonus ware examined; the changes in the tonus limbs of the cystometrograms obtained in normal animals and in those subjected to decerebration, spinal transection or section of the nervous pathways to the bladder were observed. To avoid the influence of the anesthetics on the central nervous system as well as on the bladder, local anesthesia was provided for the experiments Following results were obtained. 1 . The micturition Ehresholds were determined in terms of two different {parameters, the threshold volume and the threshold pressure; the threshold volgmes showed considerable Individual differences ranging from 25 to 85c.c. in most cases, wheeas the threshold pressures revealed less individual differences ranging from 7 to 15 cm H_(2)O in most cases. 2. The micturition pressures were from 15 to 30 cm H_(2)O in most cases, and there was no particular relationship between the threshold volumes and the micturition pressures. 3. In supracollicular decerebrated rabbits, micturition reflexes were inhibited and the increased micturition thresholds were shown in the cystometrograms. 4. In the intercollicular decerebrated, micturition reflexes were facilitated and the decreased micturition thresholds were shown in the cystometrograms. 5. The tonus limbs of the cystometrograms were not affected by the levels of decerebration. 6. Spinal transection abolished the micturition reflexes, whereas the tonus limbs of thecystometrograms were not affected. 7. Following, the sacral rhizotomy and local blocking of the pelvic nerves the micturition reflexes were abolished, but the tones limbs of the cystome-trograms were not affected. 8. Section of the sympathetic nerve (hypogastric nerve) to the bladder did not affect the micturition threshold volumes and the tonus limbs of the cystometrograms.
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