Rod-shaped particles in the plasma membrane of the mitochondria-rich cell of amphibian epidermis.

A freeze-fracture study has revealed rod-shaped intramembranous particles on the plasma membrane P-face (cytoplasmic leaflet) of the mitochondria-rich cell (or flask cell) of Xenopus laevis and Rana ridibunda epidermis. Such particles have previously been found in all other mitochondria rich cells examined by this technique, namely, the MR-cell of toad bladder epithelium, the dark cell of rat kidney collecting tubule, and the flask cell of Xenopus kidney collecting tubule. These particles are assumed, therefore, to be closely connected with the function of this cell type.