Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/32977
標題: Spinal glutamatergic NMDA-dependent cyclic pelvic nerve-to-external urethra sphincter reflex potentiation in anesthetized rats
作者: Liao, J.M.
董光中
Yang, C.H.
Cheng, C.L.
Pan, S.F.
Chen, M.J.
Huang, P.C.
Chen, G.D.
Tung, K.C.
Peng, H.Y.
Lin, T.B.
關鍵字: postvoiding potentiation
posttetanic potentiation
glutamate
long-term potentiation
lower urinary-tract
micturition-reflex
receptor antagonists
synaptic-transmission
dorsal-horn
alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid
lasting
potentiation
bladder contraction
cord-injury
期刊/報告no:: American Journal of Physiology-Renal Physiology, Volume 293, Issue 3, Page(s) F790-F800.
摘要: The purposes of this study were to investigate whether the pelvic nerve-to-external urethra sphincter (EUS) reflex potentiation can be induced under physiological conditions and to determine whether glutamatergic neurotransmission is involved in the reflex potentiation. Stimulation-evoked reflex activities, during rhythmic bladder contractions caused by a continuous saline infusion, in 21 anesthetized rats were recorded with/without the intrathecal administration of 10 mu l of CNQX ( a glutamatergic AMPA receptor antagonist; 100 mu M) and APV( a glutamatergic NMDA receptor antagonist; 100 mu M). Reflex activities became potentiated following the increment of intravesical pressure (IVP) during the storage phase (2.39 +/- 0.28 spikes/mmHg, n = 21) and the ascending period of the voiding phase (1.46 +/- 0.35 spikes/mmHg, n = 21) and decreased following the decrement of IVP during the descending period of the voiding phase (1.50 +/- 0.33 spikes/mmHg, n = 21). Although it is characterized by a low IVP, a postvoiding reflex potentiation in stimulation-evoked activities was elicited at the critical period after a voiding contraction had just finished (23.95 +/- 8.96 spikes/mmHg, n = 21). The slope of the regression line of evoked activities vs. the IVP during the storage phase was significantly (P < 0.01) higher than that of the ascending and descending periods of the voiding phase, but there was no statistical difference between the ascending and the descending periods (P > 0.05). In addition, the slope of the regression line of posttetanic reflex potentiation was significantly higher than that of the storage phase (P < 0.01). All the slopes of the regression lines decreased after intrathecal CNQX administration ( from 3.15 +/- 0.44, 2.10 +/- 0.57, 2.13 +/- 0.53, and 21.30 +/- 3.41 to 0.83 +/- 0.31, 0.74 +/- 0.12, 0.76 +/- 0.12, and 4.31 +/- 3.71 spikes/mmHg in storage, ascending and descending period of the voiding phase, and postvoiding potentiation, respectively; all P < 0.01, n = 10). The slopes of the regression lines became almost horizontal after intrathecal APV administration ( from 3.15 +/- 0.44, 2.10 +/- 0.57, 2.13 +/- 0.53, and 21.30 +/- 3.41 to 0.16 +/- 0.12, 0.21 +/- 0.07, 0.18 +/- 0.05, and 0.23 +/- 0.76 spikes/mmHg in storage, ascending and descending period of voiding phase, and postvoiding potentiation, respectively; all P < 0.01, n = 10). Our results suggest that a potentiation in the pelvic nerve-to-EUS reflex can be induced under physiological conditions and the glutamatergic mechanism appears to be involved in this reflex potentiation.
URI: http://hdl.handle.net/11455/32977
ISSN: 1931-857X
文章連結: http://dx.doi.org/10.1152/ajprenal.00296.2006
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