Department of Urology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
J Urol. 2010 Jul;184(1):386-91. doi: 10.1016/j.juro.2010.03.002. Epub 2010 May 20.
Impaired melatonin production is involved in disruption of the normal circadian pattern of sleep, which leads to nocturia in older adults. Melatonin improves nocturia. We hypothesized that melatonin could alleviate urinary frequency by suppressing the brain micturition center. We investigated the central contribution of melatonin to bladder function and urine volume.
Cystometry was done in conscious female Sprague-Dawley rats (Japan SLC, Hamamatsu, Japan). We examined the effect of melatonin alone (4.3 x 10(-1) to 4.3 x 10 pmol intracerebroventricularly) or with the gamma-aminobutyric acid(A) antagonist bicuculline (5.0 x 10(-5) mg/kg intravenously) on bladder function. The influence of melatonin (4.3 x 10 pmol intracerebroventricularly) on urine volume was investigated in water loaded rats. Blood samples were collected to determine antidiuretic hormone, atrial natriuretic peptide and brain natriuretic peptide 4 hours after melatonin administration.
Melatonin significantly increased bladder capacity dose dependently by 27.0%, 40.8% and 63.5% at 4.3 x 10(-1), 4.3 and 4.3 x 10 pmol, respectively, but had no significant effect on bladder contraction pressure. Bicuculline inhibited the melatonin induced increases in bladder capacity. Melatonin decreased urine volume in water loaded rats but plasma antidiuretic hormone, atrial natriuretic peptide and bladder contraction pressure were not changed.
Results suggest that melatonin increases bladder capacity via gamma-aminobutyric acid(A) receptor in the brain and decreases urine volume. Thus, melatonin could be beneficial for nocturia via a central nervous system effect.
褪黑素生成受损会破坏正常的睡眠昼夜节律，导致老年人夜尿增多。褪黑素可改善夜尿症。我们假设褪黑素可以通过抑制脑排尿中枢来减轻尿频。我们研究了褪黑素对膀胱功能和尿量的中枢贡献。
在清醒的雌性 Sprague-Dawley 大鼠（日本 SLC，滨松，日本）上进行膀胱测压。我们检查了褪黑素单独作用（4.3×10（-1）至 4.3×10 pmol 侧脑室注射）或与γ-氨基丁酸（A）拮抗剂印防己毒素（5.0×10（-5）mg/kg 静脉注射）联合作用对膀胱功能的影响。在水负荷大鼠中研究了褪黑素（4.3×10 pmol 侧脑室注射）对尿量的影响。褪黑素给药 4 小时后采集血样，以测定抗利尿激素、心钠肽和脑钠肽 4 水平。
褪黑素显著增加膀胱容量，在 4.3×10（-1）、4.3 和 4.3×10 pmol 时分别增加 27.0%、40.8%和 63.5%，但对膀胱收缩压无显著影响。印防己毒素抑制了褪黑素引起的膀胱容量增加。褪黑素减少了水负荷大鼠的尿量，但血浆抗利尿激素、心钠肽和膀胱收缩压没有变化。
结果表明，褪黑素通过脑内γ-氨基丁酸（A）受体增加膀胱容量，并减少尿量。因此，褪黑素可能通过中枢神经系统的作用对夜尿症有益。
