谷氨酸微注射至孤束核对大鼠胃运动的影响及其机制。
Effects and mechanisms of L-glutamate microinjected into nucleus ambiguus on gastric motility in rats.
机构信息
Shandong Normal University, Ji'nan, China.
出版信息
Chin Med J (Engl). 2010 Apr 20;123(8):1052-7.
BACKGROUND
L-glutamate (L-GLU) is a major neurotransmitter in the nucleus ambiguus (NA), which can modulate respiration, arterial pressure, heart rate, etc. This study investigated the effects and mechanisms of L-GLU microinjected into NA on gastric motility in rats.
METHODS
A latex balloon connected with a pressure transducer was inserted into the pylorus through the forestomach for continuous recording of the gastric motility. The total amplitude, total duration, and motility index of gastric contraction waves within 5 minutes before microinjection and after microinjection were measured.
RESULTS
L-GLU (5 nmol, 10 nmol and 20 nmol in 50 nl normal saline (PS) respectively) microinjected into the right NA significantly inhibited gastric motility, while microinjection of physiological saline at the same position and the same volume did not change the gastric motility. The inhibitory effect was blocked by D-2-amino-5-phophonovalerate (D-AP5, 5 nmol, in 50 nl PS), the specific N-methyl-D-aspartic acid (NMDA) receptor antagonist, but was not influenced by 6-cyaon-7-nitroquinoxaline-2,3-(1H,4H)-dione (CNQX) (5 nmol, in 50 nl PS), the non-NMDA ionotropic receptor antagonist. Bilateral subdiaphragmatic vagotomy abolished the inhibitory effect by microinjection of L-GLU into NA.
CONCLUSIONS
Microinjection of L-GLU into NA inhibits the gastric motility through specific NMDA receptor activity, not non-NMDA receptor activity, and the efferent pathway is the vagal nerves.
背景
L-谷氨酸（L-GLU）是孤束核（NA）中的主要神经递质，可调节呼吸、动脉压、心率等。本研究探讨了将 L-GLU 微注射到 NA 中对大鼠胃动力的影响及其机制。
方法
通过前胃将与压力换能器相连的乳胶气球插入幽门，以连续记录胃动力。测量微注射前和微注射后 5 分钟内胃收缩波的总幅度、总持续时间和运动指数。
结果
将 L-GLU（分别为 5 nmol、10 nmol 和 20 nmol 的 50 nl 生理盐水（PS））微注射到右侧 NA 中，可显著抑制胃动力，而在相同位置和相同体积微注射生理盐水则不改变胃动力。D-2-氨基-5-磷戊酸（D-AP5，5 nmol，在 50 nl PS），特异性 N-甲基-D-天冬氨酸（NMDA）受体拮抗剂，阻断了抑制作用，但非 NMDA 离子型受体拮抗剂 6-氰基-7-硝基喹喔啉-2,3-（1H,4H）-二酮（CNQX）（5 nmol，在 50 nl PS）不影响抑制作用。双侧膈下迷走神经切断术消除了将 L-GLU 微注射到 NA 对胃动力的抑制作用。
结论
将 L-GLU 微注射到 NA 中可通过特异性 NMDA 受体活性而不是非 NMDA 受体活性抑制胃动力，传出途径是迷走神经。
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