The chromaffin cells of Siren lacertina (Amphibia, Urodela): cytological characteristics and evidence of exocytosis.

In the adrenal gland of Siren lacertina three types of chromaffin cells are described, on the basis of size, shape and electron density of the cytoplasmic granules: adrenaline-secreting cells, noradrenaline-secreting cells and small granulated chromaffin-cells. In A-cells exocytotic profiles are described, in which the granule membrane fuses with the plasma membrane and the granule core is discharged into the intercellular space.