Jankovic Slobodan M, Jankovic Snezana V, Stojadinovic Dobrivoje, Stojadinovic Miroslav, Kostovic Vladimir, Novakovic Milan, Markovic Veroljub
Department of Pharmacology, University of Kragujevac Medical Faculty, Kragujevac, Serbia.
Urology. 2009 May;73(5):1136-9. doi: 10.1016/j.urology.2008.02.057. Epub 2008 Apr 9.
A neurotransmitter role for glutamate in the autonomous nervous system was recently demonstrated in the gastrointestinal tract, and its stimulatory effect on spontaneous motility of human ureter was shown. The aim of our study was to investigate the effects of glutamate on the release of neurotransmitters from intramural nerves of the human ureter.
The effects of exogenous glutamate were tested on electric field-stimulated contractions of isolated human ureter, taken from 16 adult patients after nephrectomy. The longitudinal tension and intraluminal pressure of the isolated ureter were recorded simultaneously. The electric field stimulation was done with square wave pulses (20 V through electrodes, 400 mA, duration 1 ms, frequency 16 Hz). The pulse trains lasted for 30 s, a with 30-s pause.
Glutamate (7.9 x 10(-6) M/L to 10.6 x 10(-3) M/L) and kainic acid (6.3 x 10(-8) M/L to 2.2 x 10(-5) M/L) produced a concentration-dependent decrease in the electric field-stimulated activity of the isolated preparations. However, N-methyl-D-aspartic acid (9.1 x 10(-8) M/L to 3.1 x 10(-5) M/L), (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (7.2 x 10(-8) M/L to 3.2 x 10(-6) M/L) and (+/-)-1-Aminocyclopentane-trans-1,3-dicarboxylic acid (7.7 x 10(-8) M/L to 6.5 x 10(-5) M/L) were ineffective. The electric field-stimulated contractions of isolated ureter were also inhibited by lidocaine (3.70 x 10(-4)M/L) and atropine (1.00 x 10(-6)M/L).
The results of our study suggest that glutamate inhibits electric field-stimulated release of acetylcholine in the human ureter through activation of kainate ionotropic receptors, located on the intramural nerve fibers.
最近在胃肠道中证实了谷氨酸在自主神经系统中具有神经递质作用，并且显示其对人输尿管的自发运动有刺激作用。本研究的目的是探讨谷氨酸对人输尿管壁内神经递质释放的影响。
测试外源性谷氨酸对取自16例肾切除术后成年患者的离体人输尿管电场刺激收缩的影响。同时记录离体输尿管的纵向张力和腔内压力。电场刺激采用方波脉冲（通过电极施加20V电压，400mA，持续时间1ms，频率16Hz）。脉冲序列持续30s，间隔30s。
谷氨酸（7.9×10⁻⁶M/L至10.6×10⁻³M/L）和 kainic 酸（6.3×10⁻⁸M/L至2.2×10⁻⁵M/L）使离体标本的电场刺激活性呈浓度依赖性降低。然而，N-甲基-D-天冬氨酸（9.1×10⁻⁸M/L至3.1×10⁻⁵M/L）、（RS）-α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（7.2×10⁻⁸M/L至3.2×10⁻⁶M/L）和（±）-1-氨基环戊烷-反式-1,3-二羧酸（7.7×10⁻⁸M/L至6.5×10⁻⁵M/L）无效。利多卡因（3.70×10⁻⁴M/L）和阿托品（1.00×10⁻⁶M/L）也抑制离体输尿管的电场刺激收缩。
我们的研究结果表明，谷氨酸通过激活位于壁内神经纤维上的海人藻酸离子型受体，抑制人输尿管中电场刺激的乙酰胆碱释放。
