Spinal glutamatergic NMDA-dependent cyclic pelvic nerve-to-external urethra sphincter reflex potentiation in anesthetized rats

Jiuan Miaw Liao, Cho Hsun Yang, Chen Li Cheng, Shwu Fen Pan, Mei Jung Chen, Pei Chen Huang, Gin Den Chen, Kwong Chung Tung, Hsien Yu Peng, Tzer Bin Lin

研究成果: 雜誌貢獻文章

16 引文 斯高帕斯(Scopus)

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 μl of CNQX (a glutamatergic AMPA receptor antagonist; 100 μM) and APV( a glutamatergic NMDA receptor antagonist; 100 μM). 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.

原文英語
期刊American Journal of Physiology - Renal Physiology
293
發行號3
DOIs
出版狀態已發佈 - 九月 2007
對外發佈Yes

ASJC Scopus subject areas

  • Physiology

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