Zhen Ci Yan Jiu. 1990 ; 15(2): 112-6.

[Effect of intracerebroventricular injection of thyrotropin releasing hormone on electro-acupuncture analgesia and the content of cerebral cAMP in rats]

Zhang Z, Tu Z, Zhu Z.

Department of physiology, Faculty of Bsic Medical Sciences, Tongji Medical University, Wuhan.

Experiments were performed on 42 female albino rats weighing from 180-250 gm. The pain threshold (PT) was determined by radiant heat induced tail-flick method. The cAMP contents in various regions of brain were measured by radio-immunoassay. Electro-acupuncture (EA) at bilateral "Zusanli" and "Sanyinjian" in rats significantly elevated PT, increased the content of cAMP in the hypophysis, while decreased that of septal nucleus. No effects were found in the basal PT and the cAMP contents of the hypophysis and septal nuclei after intraventricular injection of TRH. After TRH administered intraventricularly, however, EA didn't elevate PT, but still increased hypophysial cAMP with a decrease in the level of cAMP in the septal nucleus. These results suggest that the cAMP may be related to analgesic effect induced by EA in some brain regions, and TRH injected into cerebral ventricles can antagonize the analgesic effect caused by EA, but this effect seemed to have nn relation to the contents to the contents of cAMP of hypophysis, septal nucleus, caudatum, hypothalamus and thalamus.