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Effects of selective unilateral dorsal root(s) rhizotomy on micturition reflex in anesthetized rats
Author(s) -
Tsai MingCheng,
Tang ChihYung,
Chang YaTing,
Cheng ChenLi,
Liao JiuanMiaw,
Lee ShinDa,
Pan ShwuFen,
Chen MeiJung,
Huang PeiChen,
Lin TzerBin
Publication year - 2006
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.20211
Subject(s) - rhizotomy , medicine , anesthesia , urination , dorsum , reflex , contraction (grammar) , saline , urology , urinary system , anatomy
Abstract Purpose: To clarify the contributions of sensory inputs and glutamate transmissions to the spinal micturition reflex. Materials and Methods: Cystometrogram and external urethral sphincter electromyogram activities evaluated the L6 and/or S1 levels. Results: Changes in intravesicular pressure (IVP) in response to saline infusion (0.1 ml/min) were found after unilateral dorsal root rhizotomy at the L6 level, which showed significant increases in threshold pressure (rhizotomized vs. control: 14.25 ± 0.82 vs. 8.40 ± 0.69 cmH 2 O, P < 0.01, n = 28), post‐voiding pressure (7.66 ± 0.56 vs. 5.42 ± 0.52 cmH 2 O, P < 0.01, n = 28), holding duration (135.06 ± 23.6 vs. 77.73 ± 13.56 sec, P < 0.05, n = 28), and inter‐contraction interval (140.62 ± 23.29 vs. 82.40 ± 13.57 sec, P < 0.05, n = 28). Several (mean = 2.32 ± 1.31 vs. 0.12 ± 0.21, P < 0.01, n = 28, P < 0.01, n = 28) non‐voiding contractions with gradual increase in IVP were found ahead of voiding contraction after rhizotomy. An additional dorsal root rhizotomy at the ipsilateral S1 level caused further increases in urodynamic parameters (threshold pressure, 18.18 ± 1.67 cmH 2 O, P < 0.01; post‐voiding pressure 8.07 ± 0.96 cmH 2 O, P < 0.01; holding duration, 211.44 ± 42.54 sec, P < 0.01; inter‐contraction interval, 264.2 ± 59.99 sec, P < 0.05; non‐voiding contractions, 4.41 ± 2.12, P < 0.01, n = 7). Intrathecal glutamate (100 µM, 10 µl) ameliorated all the pathological conditions induced by unilateral dorsal root rhizotomy at the L6 level in a dose dependent manner (ED 50 = 1.25 ± 10 −5 ). Intrathecal CNQX (6‐cyano‐7‐nitroquinoxaline‐2,3‐dione; 100 µM, 10 µl) and APV ( D ‐2‐amino‐5‐phosphonovaleric acid; 100 µM, 10 µl) injections after rhizotomy at the L6 level induced disturbances similar to that caused by an additional rhizotomy at ipsilateral S1 level. Wherease, glutamate (100 µM, 10 µl) reversed the disturbances caused by CNQX but showed no effect on that by APV. Conclusions: Acute partial sensory deprivation caused acute impaired micturition reflex in rat models. In addition, glutamatergic NMDA and AMPA receptors are important for mediating these impairments in micturition reflex. Neurourol. Urodynam. 25:820–827, 2006. © 2006 Wiley‐Liss, Inc.