Electrical Activity in Single Myocardial Cells of Limulus polyphemus

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Science  03 Aug 1962:
Vol. 137, Issue 3527, pp. 340-341
DOI: 10.1126/science.137.3527.340


Single cells of the heart of Limulus were examined in situ with conventional microelectrodes. Resting and action potentials were measured in a total of 20 animals, with 25 penetrations per heart during normal spontaneous activity. Resting-potential values averaged 45 millivolts. Action potentials showed a rapid upstroke and a prolonged plateau. A small, irregular burst of electrical activity occurred during the plateau phase, a discharge presumably associated with the "neurogenic" character of the heartbeat. There was no significant overshoot, nor was there any topographical localization of action-potential "types.".