Jf. Zhang et al., THE EFFECT OF CALCITONIN-GENE-RELATED PEPTIDE ON ISCHEMIC REPERFUSION-INDUCED ARRHYTHMIAS IN RATS, International journal of cardiology, 46(1), 1994, pp. 33-36
Thirty-six wistar rats (150-250 g body weight) were randomly divided i
nto two groups. There were equal numbers of male and female rats in ea
ch group. Each group of rats was given either 0.5 mi normal saline or
calcitonin gene-related peptide (CGRP, 20 mu g/kg dissolved in 0.5 ml
normal saline) intravenously within 5 min. Coronary arteries of these
rats were occluded 5 min after administration. The coronary artery was
then released from ligation 5 min later. The heart beat of all rats w
as monitored for 30 min. An electrocardiogram was recorded using limb
leads and below-xiphoid leads. There was no ischemic reperfusion-induc
ed arrhythmia in the first minute of reperfusion in CGRP group, while
13 rats occurred ischemic reperfusion-induced arrhythmia (ventricular
tachycardia and fibrillation) in the normal saline group (P < 0.05). A
verage onset time of ischemic reperfusion-induced arrhythmia was 377.5
+/- 141.0 s/sim. In the CGRP group, compared with 42.7 +/- 55.4 s/sim
. for the normal saline group (P < 0.01). The duration of ischemic rep
erfusion-induced arrhythmia was 15.0 +/- 30.6 s/sim. In the CGRP group
compared with 104.4 +/- 143.8 s/sim. in the normal group (P < 0.05),
There was no death in the CGRP group, but six rats in the normal salin
e group died (P < 0.05). The results showed that CGRP could reduce and
delay the occurrence of ischemic reperfusion-induced arrhythmia such
as ventricular tachycardia and fibrillation, especially in the early p
eriod, and decrease the mortality. The mechanism is not clear and need
s to be studied further.