I. Elmas et al., Analysis of gastrocnemius compound muscle action potential in rat after death: significance for the estimation of early postmortem interval, FOREN SCI I, 116(2-3), 2001, pp. 125-132
The estimation of postmortem interval is of great importance in forensic me
dicine. Changes in the properties of excitable tissue provide another possi
ble means by which the time of death can be estimated. This paper reports t
he monitorization of the compound action potentials recorded from gastrocne
mius muscle by means of sciatic nerve stimulation in rats before and after
death. The sciatic nerve was stimulated using rectangular impulses of 0.1 m
s duration and intensities ranged between 1 and 100 mA while the rat was al
ive. Subsequently, the rat was killed by cervical dislocation. The similar
measurement procedure was performed at the moment of death and every 5 min
after sequentially. There was a progressive decline in amplitude values tha
t began 10 min after death. The decrease in the amplitude of the compound m
uscle action potentials (CMAP) was most prominent especially when elicited
with lower stimulus intensities. The mean area of the CMAPs also began to d
ecrease beginning from 15 min after death. Fifteen minutes after death, the
motor latencies began to prolong. Thirty-five minutes after death, the dec
line in amplitude and area of mean CMAP was most prominent as the mean moto
r latency. At the 40th minute, most of the CMAPs were unelicitable. During
the early postmortem interval, these amplitude, area and motor latency alte
rations decrease in the amplitude and area, prolongation of motor latency s
eems to be well correlated with each other and this was statistically signi
ficant. These findings are discussed as possible basis of a forensic method
for postmortem interval estimation. (C) 2001 Elsevier Science Ireland Ltd.
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