Sadamoto Satoh

Role of the Pudendal Nerves on the Dynamics of Micturition in the Dog Evaluated by Pressure Flow Emg and Pressure Flow Plot Studies

The role of the pudendal nerves on the dynamics of micturition was studied using 16 decerebrated dogs. The voiding cycles were analyzed by pressure flow EMG and pressure flow plot studies under 3 conditions: control, after unilateral, and after bilateral pudendal nerve transection. In the control condition, highly reproducible reflex micturition with bladder contraction and spasmodic rhythmic sphincter contractions was demonstrated. Two patterns were noted following pudendal nerve transection: reflex micturition and overflow incontinence. Even though reflex micturition could be achieved in 9 out of 16 dogs after bilateral transection, there was decreased bladder emptying as well as absence of spasmodic rhythmic sphincter contractions. Overflow incontinence developed in the remaining 7 dogs (5 dogs after bilateral transection and 2 dogs after unilateral transection). It appears that the pudendal nerves play an important role in emptying the bladder of the dog.

Role of striated urethral sphincter on the voiding cycle in the decerebrated dog.

The role of the striated urethral sphincter on the dynamics of micturition was studied using 4 decerebrated dogs. The voiding cycles were analyzed by pressure flow EMG and pressure flow plot studies before and after the administration of suxamethonium. In the control condition, highly reproducible reflex micturition with bladder contraction and spasmodic rhythmic sphincter contractions was demonstrated. After the administration of suxamethonium reflex micturition occurred, but there was decreased bladder emptying as well as absence of spasmodic rhythmic sphincter contractions. The striated urethral sphincter would seen to play an important role in bladder emptying of decerebrated dogs.

Urethral Response to Nerve Stimulation Measured by Strain Gauge Force Transducer

This paper presents a study of urethral responses to efferent nerve stimulation in dogs. The pelvic, hypogastric and pudendal nerves were stimulated using a programmed instrument under three different in vivo conditions. The preparations consisted of: (A) bladder, urethra, and rectum; (B) urethra and rectum, and (C) urethra only. Stimulation of the pelvic nerve in preparation A resulted in elongation and constriction of the mid and proximal urethra with a resultant rise in pressure. However, this response was reduced in preparations B and C. Similar observations were made with hypogastric nerve stimulation. The results of pudendal nerve stimulation were significantly different, in that the pressure rise occurred in the mild and distal urethra and varied in elongation response.

Effects of autonomic agonists on in vivo female canine urethral motility.

The response of the urethra to intra-arterially administered autonomic agonists was studied in vivo by measuring the motility and pressure changes in female dogs. Phenylephrine produced shortening along the transverse axis with an increase in urethral pressure in a dose-dependent manner. Isoproterenol produced lengthening along the transverse axis with a decrease in urethral pressure. Both acetylcholine and dimethylphenylpiperazinium did not produce consistent patterns in urethral response. It seems that adrenergic drugs act predominantly on the circular muscle layer and cholinergic drugs act equally on both the circular and longitudinal muscle layers.

Application of ultrasonic M-mode scanning and computer evaluation on urodynamics.

The M-mode scanning images of urethra, detrusor pressure and urine flow rate during voiding were recorded together on the line scan recorder, and allowed for plotting and calculation of some valuable urodynamic parameters by computer evaluation. This procedure will permit first application of M-mode scanning and new direction on urodynamics.