L Perales — Page 2 | Search PubMed

The authors carried out detailed experiments on cats under anaesthesia, with electrical stimulation of the L7, S1, S2 and S3 ventral roots and of the vesical detrusor in order to study their contraction. They varied the frequency, intensity and duration parameters of the stimulation beats, using as contraction index, the variations in the intravesical pressure measured by means of a urethral catheter. They controlled the intraabdominal pressure by means of a ball and juxtavesical catheter full of H2O. They investigated two main aspects: 1) The stimulation of which root is most effective, and 2) what combination of stimulation parameters produces the greatest and longest-lasting contractile response and miction. The L7 stimulation was ineffective and S2 was the root which produced the greatest increases in pressure. Increases in frequency and intensity in the course of stimulation up to 20 Hz and 6 mA were progressively more effective. The discontinued stimuli 1 s on 1 s off, were more effective, partially revealing the effects of "fatigue". Finally, the authors discuss the problems of electric stimulation of lumbo-sacral roots.

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