Electrical responses by guinea pig megakaryocytes

Abstract

THE striking similarities between blood platelets and muscle cells elucidated in recent years (for example, contractile properties, a full complement of contractile proteins, a dual canalicular system resembling the sarcoplasmic reticulum of muscle, and an active intracellular calcium pump; for review see ref. 1) suggests that the platelet might also manifest electrical activity resembling that seen in muscle. Unfortunately, the small size of the platelet (2–4 µm in diameter) has precluded study of transmembrane electrical potentials using available techniques. However, as circulating platelets represent cytoplasmic fragments of the much larger megakaryocytes, we reasoned that the megakaryocyte itself might well possess interesting electrophysiological properties. The studies described here represent our initial characterisation of membrane responses in the megakaryocyte.