Cicinelli E, Einer-Jensen N, Galantino P, Pinto V, Barba B, Tartagni M
Department of Obstetrics and Gynecology, University of Bari, Italy.
Hum Reprod. 2001 Dec;16(12):2496-500. doi: 10.1093/humrep/16.12.2496.
Low-dose vaginal oestrogens are effective in treating post-menopausal urogenital atrophy without inducing endometrial proliferation. We aimed to assess whether this dichotomic effect could be the result of a preferential vagina-to-urethra transfer via a counter-current transfer of oestrogens from vagina to the arterial blood supplying the urethra. Due to the impossibility of obtaining blood samples from urethral arteries, and since the nature of counter-current exchange of substances is similar to the transfer of heat, we investigated cold transfer throughout the anterior vaginal wall to the vesical trigone and urethra.
Plastic tubes filled with cold saline were inserted into the vagina of 30 menopausal women. Temperatures were recorded at the vesical trigone and at three different urethral sites. Comparisons were performed 2 and 4.5 min after starting of cooling, and 4.5 min after removal of tubes.
The urethra cooled significantly more than the bladder. Urethral cooling was not homogeneous; distal sites of the urethra cooled significantly more than proximal site and bladder despite a larger distance to the vaginal cooling device.
Distribution of cold from the vagina to the urethra is not the result of simple diffusion and mechanisms of preferential distribution may exist from the vagina to the middle and low part of the urethra.
低剂量阴道雌激素可有效治疗绝经后泌尿生殖系统萎缩，且不会诱发子宫内膜增生。我们旨在评估这种二分效应是否可能是由于雌激素从阴道向供应尿道的动脉血进行逆流转移，从而优先从阴道转移至尿道所致。由于无法从尿道动脉采集血样，且物质逆流交换的性质与热量传递相似，我们研究了从前阴道壁到膀胱三角区和尿道的冷传递情况。
将充满冷盐水的塑料管插入30名绝经后女性的阴道。在膀胱三角区和三个不同的尿道部位记录温度。在开始冷却后2分钟和4.5分钟以及取出管子后4.5分钟进行比较。
尿道降温明显超过膀胱。尿道降温不均匀；尽管尿道远端部位距离阴道冷却装置更远，但尿道远端部位的降温明显超过近端部位和膀胱。
从阴道到尿道的冷分布不是简单扩散的结果，可能存在从阴道到尿道中下部的优先分布机制。
