年轻和老年雌性犬尿道平滑肌的收缩特性：形态学和药理学方面
Contractile properties of urethral smooth muscles of young and aged female dogs: morphological and pharmacological aspects.
作者信息
Ahmed H, Moriyama N, Fukasawa R, Nishimatsu H, Tanaka Y, Kitamura T, Tatemichi S, Akiyama K, Suzuki Y, Aisaka K
机构信息
Department of Urology, Faculty of Medicine, The University of Tokyo, Japan.
出版信息
Int J Urol. 2000 Aug;7(8):298-306. doi: 10.1046/j.1442-2042.2000.00198.x.
BACKGROUND
Alpha1-adrenoceptors are highly concentrated in the urethral smooth muscles and may play an important role in the contraction of this area. However, detailed examinations of age-related changes of the properties of urethral smooth muscle have rarely been undertaken.
METHODS
The contractile properties of urethras from young non-parous and old parous female beagles were determined with a urethral function study, macroscopic autoradiography for urethras using [3H]-labeled tamsulosin and morphometry of the urethral muscles.
RESULTS
The antagonistic effect (pA2) of prazosin for norepinephrine was 7.76+/-0.13 in young dogs and 7.62+/-0.06 in aged dogs. The specific binding of [3H]-tamsulosin (a relatively selective alpha1A-adrenoceptor antagonist) was recognized diffusely in proximal urethras with in vitro autoradiography. The density of binding in smooth muscles was approximately 60 and 40% in circular longitudinal layers, respectively, for both dogs.
CONCLUSIONS
The female canine urethra had alpha1A, and alpha1L-adrenoceptors. No age-related changes were seen in the function of the proximal urethra, distribution of alpha1-adrenoceptor binding sites and smooth muscle densities.
背景
α1肾上腺素能受体高度集中于尿道平滑肌，可能在该区域的收缩中发挥重要作用。然而，很少有人对尿道平滑肌特性的年龄相关变化进行详细研究。
方法
通过尿道功能研究、使用[3H]标记的坦索罗辛对尿道进行宏观放射自显影以及尿道肌肉的形态计量学，测定年轻未生育和老年已生育雌性比格犬尿道的收缩特性。
结果
哌唑嗪对去甲肾上腺素的拮抗作用（pA2）在幼犬中为7.76±0.13，在老年犬中为7.62±0.06。通过体外放射自显影，[3H]坦索罗辛（一种相对选择性的α1A肾上腺素能受体拮抗剂）的特异性结合在近端尿道中广泛可见。两种犬的环形纵向层平滑肌中的结合密度分别约为60%和40%。
结论
雌性犬尿道具有α1A和α1L肾上腺素能受体。近端尿道功能、α1肾上腺素能受体结合位点分布和平滑肌密度未见与年龄相关的变化。
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