Estrous cycle variation of TRPV1-mediated cross-organ sensitization between uterus and NMDA-dependent pelvic-urethra reflex activity

Hsien Yu Peng, Pei Chen Huang, Jiuan Miaw Liao, Kwong Chung Tung, Shin Da Lee, Chen Li Cheng, Jyh Cherng Shyu, Cheng Yuan Lai, Gin Den Chen, Tzer Bin Lin

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Cross-organ sensitization between the uterus and the lower urinary tract (LUT) underlies the high concurrence of pelvic pain syndrome and LUT dysfunctions, and yet the role of gonadal steroids is still unknown. We tested the hypothesis that cross-organ sensitization on pelvic-urethra reflex activity caused by uterine capsaicin instillation is estrous cycle dependent. When compared with the baseline reflex activity (1.00 ± 0.00 spikes/stimulation), uterine capsaicin instillation significantly increased reflex activity (45.42 ± 9.13 spikes/stimulation, P <0.01, n = 7) that was corroborated by an increase in phosphorylated NMDA NR2B (P <0.05, n = 4) but not NR2A subunit (P > 0.05, n = 4) expression. Both intrauterine pretreatment with capsazepine (5.02 ± 2.11 spikes/stimulation, P <0.01, n = 7) and an intrathecal injection of AP5 (3.21 ± 0.83 spikes/stimulation, P <0.01, n = 7) abolished the capsaicin-induced cross-organ sensitization and the increment in the phosphorylated NR2B level (P <0.05, n = 4). The degrees of the cross-organ sensitization increased in a dose-dependent manner with the concentration of instilled capsaicin from 100 to 300 μM in both the proestrus and metestrus stages, whereas they weakened when the concentrations were higher than 1,000 μM. Moreover, the cross-organ sensitization caused by the uterine capsaicin instillation increased significantly in the rats during the proestrus stage when compared with the metestrus stage (P <0.01, n = 7). These results suggest that estrogen levels might modulate the cross-organ sensitization between the uterus and the urethra and underlie the high concurrence of pelvic pain syndrome and LUT dysfunctions.

Original languageEnglish
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume295
Issue number3
DOIs
Publication statusPublished - Sep 2008
Externally publishedYes

Keywords

  • Capsaicin
  • Central sensitization
  • N-methyl-D-aspartate
  • Pelvic pain syndrome
  • Spinal cord
  • Spinal reflex potentiation
  • Transient receptor potential vanilloid subfamily member 1

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Endocrinology, Diabetes and Metabolism

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