AIM: The cardioprotective effect of calcitonin gene
related peptide (CGRP) was investigated in an ischemia
rat model. METHODS: Ischemia-reperfusion injury
was provoked by 60 min left main coronary artery occlu
sion followed by 60 min of reperfusion in anesthetized
rats. The transverse slices of ventricles were stained by
2,3,5-triphenyltetrazolium chloride to determine the in
farct area. Plasma creatine phosphokinase levels were
determined by means of a creatine phosphokinase (CPK)
kit. A radioimmunoassay was used to determine plasma
CGRP levels. RESULTS: Intravenous infusion of
CGRP (1 nmol· kg- 1·h-1) 10 min before occlusion until
the end of reperfusion reduced infarct size by 89 % ±
5 %. The reduction in infarct size was accompanied by
a decrease in circulating levels of creatine phosphokinase.
Infusion of the same dose of CGRP commehcing from the
start of reperfusion until its end induced a 40 % ± 3 %
reduction of the infarct size. The cardioprotective effects
of CGRP were blocked by the novel CGRP antagonist
BIBN4096BS (20 nmol· kg-1 · h-1 ). Although cardiac
ischemia resulted in an almost 50 % increase in plasma
CGRP levels in blood sampled from right cardiac ventri
cle, intravenous infusion of the CGRP antagonist
BIBN4096BS before occlusion until the end of reperfusion
had no statistically significant effect on the infarct size.
CONCLUSION: The present study demonstrates that
CGRP is a potent myocardial protective substance.