[Protective effect of tetramethylpyrazine on the respiratory inhibition induced by hypoxia in rats].
OBJECTIVE
To study the protective effect of tetramethylpyrazine (TMP) on the respiratory inhibition induced by hypoxia.


METHODS
Forty-four SD rats were used. The hypoxic rat model was established. The effects of TMP on the responses of respiratory activity and life time to hypoxia were observed. The Nissl's staining and immunohistochemical technique were used to investigate the effect of hypoxia on the Nissl's bodies and FOS expression in the brainstem and the antagonistic action of TMP.


RESULTS
In contrast to the group of hypoxia, the occurrence of respiratory inhibition was delayed and the life time was prolonged obviously in the rats of hypoxia plus TMP (P<0.01). Compared with the air contronl group, the intensity of the Nissl's staining of the brainstem neurons became weaker in the group of hypoxia, but in the group of hypoxia plus TMP, the Nissl's staining was stronger and the gray degree decreased obviously, compared with the group of hypoxia (P<0.05). FOS positive neurons were induced by hypoxia and mainly existed in the nucleus of solitary tract, area postrema, hypoglossal nucleus, lateral reticular nucleus, inferior olivary nucleus, nucleus raphe pallidus, facial nucleus, trapezoid nucleus, but in the group of hypoxia plus TMP, the level of FOS immunoreactivity decreased remarkably, compared with the group of hypoxia (P<0.05).


CONCLUSIONS
TMP has protective effect on the respiratory inhibition induced by hypoxia and FOS may be involved in the protection.
Li
Li
L
Department of Physiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
Li
Zi-cheng
ZC
Yan
Heng-xiu
HX
Hu
Hai-yan
HY
Chen
Li
L
Yang
Wen-xing
WX
Zheng
Yu
Y
D000818:Animals; D001933:Brain Stem / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D000860:Hypoxia / Q000150:complications*; D008297:Male; D020011:Protective Agents / Q000494:pharmacology / Q000627:therapeutic use; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D011719:Pyrazines / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000187:drug effects*; D012131:Respiratory Insufficiency / Q000209:etiology / Q000517:prevention & control*
D020011:Protective Agents; D016760:Proto-Oncogene Proteins c-fos; D011719:Pyrazines; C017953:tetramethylpyrazine