Further Observations of the Detrusor Electromyogram

Abstract

Using sophisticated recording equipment and two fine copper wire electrodes introduced through the cystoscope into the bladder muscle of conscious patients at cystoscopy, reproducible electromyographic recordings were obtained from the normal and the neuropathic bladders of a group of patients. By means of simultaneous recording of the electromyographic activity of the rectus abdominis muscle in these patients, it was found that, in general, the variations in electromyographic activity of the normal bladder with filling and voiding are quite independent of abdominal muscle activity. The upper motor neuron bladders by a way of contrast showed continuing electrical activity even at rest and this activity increases with abdominal contraction. Lower motor neuron bladders remain electrically silent at all times including during abdominal muscle contraction. This suggests that the bladder electrodes do not record remote muscle activity from the abdomen or elsewhere and confirms the validity of the detrusor EMG.

Electrophysiological properties of the bladder

“…However, attempts to record EMG signals which can be attributed to detrusor muscle contractile have proved notoriously difficult. Several groups have reported such EMG activity [1], the most careful study of which isolated a component of the signal in the frequency range 10-40 Hz, which was attributed to detrusor smooth muscle contraction [2]. However, these studies have been criticized as the signals may have been contaminated by other electrical potentials, arising from pelvic floor musculature, other abdominal smooth muscles and the ECG, as well as by mechanical artifacts from bladder and urethral contraction physically moving the recording electrodes [3].…”

“…They can be measured in many smooth muscle cells, including detrusor when the intracellular Ca 2 § is increased. STICs are Ca2 § C1-channels that generate inward currents on activation, thereby causing membrane depolarization [1,2]. STICs can be blocked by the C1-channel blocker niflumic acid, which has no effect on STOCs [33].…”

Introduction to this Special Issue on Neurology

“…The interpretation of recordings is controversial and reports in literature show considerable variation on signal amplitude, frequency and shape (Corey et al, 1951;Boyce, 1952;Franksson & Petersen, 1953;Brunsting, 1958;Fredericks et al, 1969;Stanton et al, 1973Stanton et al, , 1974Cosgrove et al, 1974Cosgrove et al, , 1977Jones et al, 1974;Doyle et al, 1975;La Joie et al, 1975;Craggs & Stephenson, 1976, 1982, 1985Kaplan et al, 1976;Kaplan et al, 1976;Abdel-Rahman et al, 1982;Takaiwa et al, 1983aTakaiwa et al, , 1983bTakaiwa et al, , 1992Takaiwa & Shiraiwa, 1984;Jünemann et al, 1994;Shafik, 1994).…”

A Method for the Electromyographic Mapping of the Detrusor Smooth Muscle

“…Unfortunately, detrusor EMG has been accompanied by many problems during the last 45 years, leading to contradictory reports in the literature (Corey et al, 1951;Boyce, 1952;Franksson & Petersen, 1953;Brunsting, 1958;Fredericks et al, 1969;Stanton et al, 1973Stanton et al, , 1974Cosgrove et al, 1974Cosgrove et al, , 1977Jones et al, 1974;Doyle et al, 1975;La Joie et al, 1975;Craggs & Stephenson, 1976, 1985Kaplan et al, 1976;Abdel-Rahman et al, 1982;Takaiwa et al, 1983aTakaiwa et al, , b, 1992Takaiwa & Shiraiwa, 1984;Jünemann et al, 1994;Shafik, 1994). To review common problems of detrusor EMG to date, five exemplary cases will be discussed (Corey et al, 1951;Boyce, 1952;Brunsting, 1958;Stanton et al, 1973Stanton et al, , 1974Doyle et al, 1975;Craggs & Stephenson, 1976, 1985Takaiwa et al, 1983aTakaiwa et al, ,b, 1992Takaiwa & Shiraiwa, 1984).…”