Jankovic Slobodan M, Jankovic Snezana V, Stojadinovic Dobrivoje, Jakovljevic Mihajlo, Milovanovic Dragan
Pharmacology Department, Medical Faculty, University of Kragujevac, Kragujevac, Serbia.
Int J Urol. 2007 Sep;14(9):833-7. doi: 10.1111/j.1442-2042.2007.01834.x.
While the neurotransmitter role of glutamate in the gastrointestinal tract has been shown, its effects on smooth muscle of the human ureter have not previously been investigated. In our study we have investigated the effects of exogenous glutamate on the spontaneous activity of isolated human ureter, taken from 14 adult patients after nephrectomy.
The segment of ureter, excised 3 cm distal from the pyeloureteral junction, was isolated in an organ bath. Both longitudinal tension and intraluminal pressure of the segment were recorded simultaneously.
Glutamate administered in the lumen of the isolated ureteral segments (7.8 x 10(-7) M/L-3.5 x 10(-2) M/L) was ineffective. When added to the isolated organ bath from the serous side of the ureteral segment, glutamate (7.9 x 10(-6) M/L-10.6 x 10(-3) M/L) and N-Methyl-D-aspartic acid (NMDA) (9.1 x 10(-8) M/L-3.1 x 10(-5) M/L) produced a concentration-dependent increase in spontaneous activity of the isolated preparations, while kainic acid (6.3 x 10(-8) M/L-10.5 x 10(-5) M/L) and (+/-)-trans-1-Aminocyclopentane-trans-1,3-dicarboxylic acid (ACPD) (7.7 x 10(-8) M/L -6.5 x 10(-5) M/L) were ineffective.
The results of our study suggest that an excitatory neurotransmitter glutamate stimulates spontaneous activity of the human ureter through activation of NMDA ionotropic receptors, located on smooth muscle cells or intramural nerve fibers.
虽然已证实谷氨酸在胃肠道中具有神经递质作用，但此前尚未研究其对人输尿管平滑肌的影响。在我们的研究中，我们研究了外源性谷氨酸对取自14例成年肾切除患者的离体人输尿管自发活动的影响。
从肾盂输尿管连接处远端3 cm处切除输尿管段，置于器官浴槽中分离。同时记录该段输尿管的纵向张力和腔内压力。
在离体输尿管段管腔内给予谷氨酸（7.8×10⁻⁷ M/L - 3.5×10⁻² M/L）无效。当从输尿管段浆膜侧加入到离体器官浴槽中时，谷氨酸（7.9×10⁻⁶ M/L - 10.6×10⁻³ M/L）和N-甲基-D-天冬氨酸（NMDA）（9.1×10⁻⁸ M/L - 3.1×10⁻⁵ M/L）可使离体标本的自发活动呈浓度依赖性增加，而 kainic 酸（6.3×10⁻⁸ M/L - 10.5×10⁻⁵ M/L）和（±）-反式-1-氨基环戊烷-反式-1,3-二羧酸（ACPD）（7.7×10⁻⁸ M/L - 6.5×10⁻⁵ M/L）无效。
我们的研究结果表明，兴奋性神经递质谷氨酸通过激活位于平滑肌细胞或壁内神经纤维上的NMDA离子型受体来刺激人输尿管的自发活动。
