Effect of tetramethylpyrazine on the responses of respiration and expression of nNOS in brainstem to hypoxia in rats

• Published in: Sheng li hsüeh pao Vol. 57; no. 2; p. 147
• Main Authors: Li, Zi-Cheng, Li, Li, Yan, Heng-Xiu, Hu, Hai-Yan, Ma, Yu-Qiong, Yang, Wen-Xing, Chen, Li, Zheng, Yu
• Format: Journal Article
• Language: Chinese
• Published: China 25.04.2005
• Subjects: Animals; Brain Stem - enzymology; Brain Stem - physiopathology; Female; Hypoxia - physiopathology; Male; Nitric Oxide Synthase Type I - genetics; Nitric Oxide Synthase Type I - metabolism; Pyrazines - pharmacology; Random Allocation; Rats; Rats, Sprague-Dawley; Respiration - drug effects; Respiratory Insufficiency - prevention & control
• ISSN: 0371-0874

The aim of the present study was to investigate the effect of tetramethylpyrazine (TMP) on the changes of respiration and expression of neuronal nitric oxide synthase (nNOS) in brainstem induced by hypoxia in the rats. Hypoxia was induced by inhalation of 8% O2-balanced N2.The electromyogram (EMG) of diaphragm was monitored to evaluate the respiratory response of the rats to hypoxia. The immunohistochemical staining technique was used to study the change of the expression of nNOS in the brainstem during hypoxia. In the rats of hypoxia group, a successive process of response, excitatory followed by inhibitory, was produced. Twenty min after hypoxia, a significant inhibition of respiration occurred, which was characterized with a marked decrease in the inspiratory duration, the respiratory frequency, and the amplitude of inspiration and a prolongation of expiratory duration (P<0.05). In the rats of pretreated with TMP, the respiratory activity was not obviously depressed (P>0.05). In the rats of hypoxia group,