Kruse M N, Belton A L, de Groat W C
Department of Pharmacology, University of Pittsburgh, Pennsylvania 15261.
Am J Physiol. 1993 Jun;264(6 Pt 2):R1157-63. doi: 10.1152/ajpregu.1993.264.6.R1157.
Spinal cord injury (SCI) in humans results in inappropriate contractions of the external urethral sphincter muscle (EUS) during micturition (bladder-sphincter dyssynergia), leading to urinary retention. The major goal of this study was to determine whether SCI in rats has similar detrimental effects on micturition. After chronic SCI, urethan-anesthetized rats had a significantly (15-fold) increased bladder capacity and impaired voiding (31-fold increase in residual volume) compared with control rats. Bladder contractions in SCI rats were accompanied by abnormal tonic EUS electromyographic activity, whereas the EUS electromyograms of control rats exhibited a burst pattern (4-8 Hz) during voiding. Suppression of EUS activity with neuromuscular blockade did not improve the fraction of urine voided in SCI rats and reduced the fraction voided in control rats. Therefore, both tonic activity and complete quiescence of the rat's EUS appear to be detrimental to voiding, suggesting that the normal bursting EUS activity facilitates bladder emptying. In summary, rats and humans exhibit similar micturition dysfunctions after SCI (e.g., bladder-sphincter dyssynergia and impaired voiding).
人类脊髓损伤（SCI）会导致排尿期间尿道外括约肌（EUS）出现不适当收缩（膀胱括约肌协同失调），进而导致尿潴留。本研究的主要目的是确定大鼠脊髓损伤是否对排尿有类似的有害影响。与对照大鼠相比，慢性脊髓损伤后，经乌拉坦麻醉的大鼠膀胱容量显著增加（15倍），排尿功能受损（残余尿量增加31倍）。脊髓损伤大鼠的膀胱收缩伴有尿道外括约肌异常的强直性肌电图活动，而对照大鼠的尿道外括约肌肌电图在排尿期间呈现突发模式（4-8赫兹）。用神经肌肉阻滞剂抑制尿道外括约肌活动并不能提高脊髓损伤大鼠的排尿比例，反而降低了对照大鼠的排尿比例。因此，大鼠尿道外括约肌的强直性活动和完全静止似乎都对排尿有害，这表明正常的突发尿道外括约肌活动有助于膀胱排空。总之，大鼠和人类在脊髓损伤后表现出相似的排尿功能障碍（如膀胱括约肌协同失调和排尿功能受损）。
