EXPERIMENTAL STUDIES ON THE NEUROGENIC BLADDER

XV. FUNDAMENTAL ANALYSIS ON THE NATURE OF CYSTOMETROGRAM

Abstract

Up to the present, we have many reports on the neurophysiology of the urinary bladder. These are, however, mostly depending upon classical concepts on the autonomic nervous system. Since physiological significance of the cystometrogram was evaluated on such bases, there could be found some clinical contradictions between actual micturition activity and results of the cystometrogram. Recently, concerning the importance of diagnosis and therapy on the neurogenic bladder, it has been required to establish a clinical value of the cystometrogram. So that, to clarify the physiological meaning of the cystometrogram on the functional activity of the normal and neurogenic bladder, following experiments were performed using adult dogs.
With selective electrical stimulation on various regions of the sacral cord, as well as the sacral, hypogastric, and pelvic nerves, the physiological contribution of each nervous element against vesical contraction was analysed.
Furthermore, on the experimental neurogenic bladder of dogs, which were induced by the surgical section of the respective sacral nerve root, the cystometrogram and cystogram were obtained. Several theoretical parameters were set and compared with each other using the actually measured values on these examinations.
Following the electrical stimulation on the sacral cord, the main efferent pathway from the sacral cord to the bladder was estimated as originated from the ventral or lateral horn of the cord, and reached to the bladder via the ventral root and the pelvic nerve. Besides this, another efferent pathway, such as originated from the dorsal horn of the sacral cord, and passed down to the bladder via the dorsal root and the pelvic nerve was estimated. Furthermore, the latter would receive partially some requlatory effect by the dorsal root ganglion. However, neither the interneurons connected to the ventral horn nerve cells from the lateral or dorsal end-apparatus of the afferent systems nor that as the element of reccurrent inhibition system to the efferent system in the ventral horn existing in the ventral root itself, could be confirmed.
On the other hand, with the selective section of the spinal cord or the peripheral nerves to the bladder, some functional relations of the higher center to the vesical efferent nerve center in the ventral horn of the sacral cord was assumed as well as that of the hypogastric nerve to the vesical efferent nerve center in the dorsal horn of the cord. However, the inhibitory system to the dorsal efferent pathway entering the sacral cord via the ventral root could not be confirmed as well as the role of efferent nerve fibers in the dorsal root of the sacral cord which do not have any synaps in the dorsal root ganglia.
The interaction of the lumbar nerve system to the sacral activity was rather clearly found, but a direct effect of the hypogastric nerve activity and that of the lower sympathetic trunk to the sacral contraction of the bladder could not be confirmed. However, some intraspinal interaction could be assumed.
On the other hand, it was possible to define the hypertonic or hypotonic state of the bladder by measured values on cystometrographic components, but it was not possible to do so from that of the cystogram. Therefore, it has been tried to state the biological condition of the bladder by available parameters obtained from a geographic dimension of the cystometrogram and cystogram. For this purpose, parameters calculated from the increment of the intravesical pressure and that from the stretching rate of the vesical wall were most valuable. The former is to be obtained directly from the measurement of cystometrographic components. However, from the latter nothing could be learned.
To analyse the latter, mural tension of the vesical wall (T), a pure physical function, was induced as the parameter, and a constant R (P·V/T) was derived from the comparison of it with mechanical stimuli (P·V) by intrav