Fine structure of the accessory boring organ of starved and satiated specimens of Ocinebrina edwardsi (Payr.)

In accessory boring organ (ABO) gland cells of fed specimens of Ocinebrina edwardsi (Payr.) there is only one kind of cell which synthesizes proteins. The newly produced secretion granules in the rough endoplasmic reticulum are small and unstructured; furthermore, they present electron dense areas in a homogeneous matrix. In the subepithelial gland cells there are granules ordered in concentric and alternate electron opaque and electron translucent rings. The granules, expelled into the ABO internal cavity (which opens in the sole of the foot) conserve their morphological structure and do not fuse with the cell plasmatic membrane. Several synapses containing vesicles with an electron dense core are present between gland cells. In ABO gland cells of starved animals the homogeneous granules are almost lacking and only structured ones are present. Activity of the ABO and the production of secretion is controlled by the nervous system through feedback signals related to the boring activity.