Fukasawa R, Taniguchi N, Moriyama N, Ukai Y, Yamazaki S, Ueki T, Kameyama S, Kimura K, Kawabe K
Department of Urology, Faculty of Medicine, The University of Tokyo, Japan.
Br J Urol. 1998 Nov;82(5):733-7. doi: 10.1046/j.1464-410x.1998.00845.x.
To identify the alpha1-adrenoceptor subtypes present in the human urethra, by comparing the affinity of prazosin for alpha1-adrenoceptors in the rabbit, dog and human prostatic urethra, and in the dog and human prostate.
The study comprised samples of human prostate and prostatic urethra, obtained by open prostatectomy of patients with benign prostatic hyperplasia, and of the proximal urethra and prostate from male Beagle dogs and rabbits. Specimens were homogenized, filtered and pelleted by centrifugation. Nonspecific binding was determined in the presence of 1 mmol/L prazosin when assessing [3H]YM-617 (tamsulosin) binding, and 10 mmol/L phentolamine when assessing [3H]prazosin binding. Specific binding was defined as the difference between total binding and nonspecific binding.
The dissociation constant for [3H]prazosin in the human prostate (0.088 nmol/L) was less than that in the rabbit urethra (0.299 nmol/L), dog urethra (0.604 nmol/L), dog prostate (0.482 nmol/L) and human urethra (0.254 nmol/L). The affinity of prazosin was also investigated by determining the potency of the inhibition of [3H]YM-617 binding. The affinity of prazosin for alpha1-adrenoceptors in the human urethra (Ki, 2.5 nmol/L) was lower than its affinity for alpha1-adrenoceptors in the human prostate (Ki, 0.25 nmol/L) and all of the cloned subtypes (Ki, 0.26-0.44 nmol/L).
The alpha1L-adrenoceptor subtype is more prominent in the human, rabbit and dog urethra and dog prostate than in the human prostate.
通过比较哌唑嗪对兔、犬和人前列腺尿道以及犬和人前列腺中α1 - 肾上腺素能受体的亲和力，确定人尿道中存在的α1 - 肾上腺素能受体亚型。
本研究包括通过对良性前列腺增生患者进行开放性前列腺切除术获得的人前列腺和前列腺尿道样本，以及雄性比格犬和兔的近端尿道和前列腺样本。将标本匀浆、过滤并通过离心沉淀。在评估[3H]YM - 617（坦索罗辛）结合时，在1 mmol/L哌唑嗪存在的情况下测定非特异性结合；在评估[3H]哌唑嗪结合时，在10 mmol/L酚妥拉明存在的情况下测定非特异性结合。特异性结合定义为总结合与非特异性结合之间的差值。
[3H]哌唑嗪在人前列腺中的解离常数（0.088 nmol/L）低于兔尿道（0.299 nmol/L）、犬尿道（0.604 nmol/L）、犬前列腺（0.482 nmol/L）和人尿道（0.254 nmol/L）中的解离常数。还通过测定对[3H]YM - 617结合的抑制效力来研究哌唑嗪的亲和力。哌唑嗪对人尿道中α1 - 肾上腺素能受体的亲和力（Ki，2.5 nmol/L）低于其对人前列腺中α1 - 肾上腺素能受体的亲和力（Ki，0.25 nmol/L）以及所有克隆亚型的亲和力（Ki，0.26 - 0.44 nmol/L）。
α1L - 肾上腺素能受体亚型在人、兔和犬的尿道以及犬前列腺中比在人前列腺中更突出。
