Effect of injury to the dorsal funiculus of the thoracic spinal cord on micturition in decerebrate and freely-moving cats.
Bladder sensation is transmitted both via the spinothalamic tract in the lateral funiculus and the dorsal system in the dorsal funiculus. We transected the dorsal funiculus in 10 female cats to clarify the functional roles of these two ascending pathways. The dorsal funiculus was transected at T10 in 5 decerebrate and 5 freely-moving cats, and micturition parameters were compared before and after transection. Transection of the dorsal funiculus did not affect any of the parameters of reflex micturition in the 5 decerebrate cats. Within 1 week after transection, 4 of the 5 freely-moving cats used the normal micturition posture, but the remaining one performed micturition in a prone position as if she had lost micturition sensation. All 5 cats urinated with a normal micturition posture by 2 weeks after transection. The mean single voided volume was decreased transiently up to 1 week, but returned to normal by 2 weeks after transection. None of the 5 cats had any residual urine before and after transection. Both the ascending and descending limbs of the micturition reflex pass through the lateral funiculus. Bladder sensation is transmitted both via the spinothalamic tract coursing in the lateral funiculus and the dorsal system in the dorsal funiculus. The dorsal system may play a major role in the transmission of bladder sensation to the cerebral cortex, but may not be essential.
Sugaya
K
K
Department of Urology, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan. sugaya@med.u-ryuku.ac.jp
Ogawa
Y
Y
Hatano
T
T
Koyama
Y
Y
Miyazato
T
T
Oda
M
M
D000818:Animals; D002415:Cats; D003655:Decerebrate State / Q000503:physiopathology*; D005260:Female; D012018:Reflex / Q000502:physiology; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013133:Spinothalamic Tracts / Q000502:physiology; D013904:Thoracic Vertebrae; D001743:Urinary Bladder / Q000294:innervation; D014554:Urination / Q000502:physiology*