Studies on the relationship between the catecholamine distribution in the atrium and the specific granules present in atrial muscle cells1.

Electron microscopy of mammalian atrial muscle cells reveals a population of specific granules suggesting that the atrial muscle cells may have a secretory function. As a preliminary step towards the investigation of the function of the specific granules, a procedure was designed to isolate these particles by differential and density gradient centrifugation of rat atrial homogenates. The specific granule preparation obtained showed a considerable degree of purification with respect to marker enzymes. The isolated granules retained their in situ fine structure and staining properties. [ABSTRACT FROM PUBLISHER]