[Effect of calcium overload and platelet activating factor on calcitonin gene related peptide release from lung tissue].
The level of calcitonin gene related peptide (CGRP) in plasma and pulmonary lavage fluid was tested by radio-immunoassay on intestinal ischemia/reperfusion (I/R) injured rat. The results showed that plasma CGRP after I/R was 161.3% more than control, and 117.8% when pre-treated with platelet activating factor (PAF) receptor antagonist SR27417A before injury but no obvious changes were observed in the sham group. Meanwhile, CGRP was reduced by 17.4% in pulmonary lavage fluid in I/R animal and elevated by 97.9% in SR27417A pre-treated animal, compared with normal control. Furthermore, it was demonstrated that CGRP release from lung tissue was enhanced concentration-dependently by calcium ionophores A23187 or PAF, as a result of blockage by phospholipase A2 inhibitor p-BPB or SR27417A respectively. In vitro experiment, CGRP in pulmonary lavage fluid was 144.6% more than control when pre-treated with SR27417A and 114.6% less than that treated with A23187 only, even 14.8% less than control. Much the same, CGRP release was 13.7% less than that treated with PAF and was 55.6% more than control when pre-treated with SR27417A only. All these results indicated that (1) CGRP was significantly increased in plasma but without obvious changes in pulmonary lavage fluid following I/R injury; (2) lung tissue CGRP release may be related with Ca2+ increase in cells or phospholipase A2 activation as well as PAF increase; (3) SR27417A was a kind of strong reagent, which may promote CGRP release in vivo and in vitro, but block the effect of PAF on CGRP release.
Yan
G T
GT
Laboratory of Biochemistry, Clinic Institution of Medicine, General Hospital of People's Liberation Army, Beijing 100853.
Wang
L H
LH
Xin
H
H
Li
Z J
ZJ
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D066298:In Vitro Techniques; D007422:Intestines / Q000098:blood supply; D008168:Lung / Q000378:metabolism*; D008297:Male; D010972:Platelet Activating Factor / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000378:metabolism
D010972:Platelet Activating Factor; D015740:Calcitonin Gene-Related Peptide; D002118:Calcium