Experimental studies on the neurogenic bladder. XII. Changes of urethral resistance after section of various nerves

Abstract

In our department, an experimental study on the vesical dysfunction after injury on the nervous system innervating the urinary bladder was already performed relating to the clinical aspect and available therapy of “Neurogenic Bladder”. However, there could scarcely be found an experimental observation of the urethral function after injury on the nerves innervating the urethra. Therefore, I had tried to examine on the relationship between the urethral function and the innervation on it, with the observation on the progressive change in urethral resistance following various sections of nerves of 68 adult male dogs. Next, I had investigated on the alteration of urethral resistance after the additional section of various nerves of animals in which sections of the nerves described above were previously performed. Furthermore, medical or surgical nerve blocks were performed on the clinical neurogenic bladder and its effect on the urethral resistance as well as on the micturition state were observed.With the experimental examination on the available condition for the estimation of urethral resistance, species of the animal, sex, body weight, depth of general anesthesia, and intravesical content are thought to be main factors affecting the results. So, I had determined the urethral resistance of male adult dogs, 10-20Kg in body weight, below 100 cc of intravesical content, light anesthesia just diminishing the palpebration reflex, with retrograde and descending watercolumn manometric technique, and obtained 55.04±4.68cmH2O as the normal value.First, bilateral section of the hypogastric or the pelvic nerve of male adult dog was performed. A spontaneous and very slight decrease of urethral resistance was observed in both cases just after the operation. However, with bilateral section of the pudendal nerve, a significant decrease of urethral resistance (57% of preoperative value) was remarkable, which was continued during about 1 month and then recovered slowly. It showed a value of only about 70% of preoperative state even 3 months after the operation. With unilateral section of the pudendal nerve, also there could be found a similar change of urethral resistance compared to that observed after bilateral section of the nerve. But it showed a value of about 70% of preoperative state just after the operation, while it was about 89% of that 3 months after the operation.Second, selective section of the 1st, 2nd, and 3rd sacral nerve roots, such as bilateral section of the ventral root, the dorsal root, the ventral-and-dorsal roots, the spinal ganglion, the ventral root-and-spinal ganglion, and these were spinal origin of the pudendal nerve, was performed. With the section of these nerve roots, urethral resistance had showed very similar change compared to that obtained after bilateral section of the pudendal nerve. The decrease of urethral resistance after the section of the ventral-and dorsal roots and/or that of the ventral root-and-spinal ganglion were rather dominant compared to that after the section of the individual sacral root, however, it could not be clarified the role of the sacral spinal ganglion on the urethral function.On the other hand, bilateral section of the pudendal nerve was performed in the animals in which bilateral section of the pelvic nerve was preceded before 1 month, but urethral resistance of these animals after the additional section of nerve showed a similar change which was found after the section of the pudendal nerve of normal animal. Next, bilateral section of the hypogastric nerve was performed 1 month after bilateral section of the pudendal nerve of the same animal. But there could not be found any effect of additional section of nerve on the urethral resistance which decreased after the section of the pudendal nerve. However, after various section of the sacral nerve root in animals in which bilateral section of the pudendal nerve was performed previously