Phosphatases in the accessory respiratory organs of two fresh-water fishes.

The distribution of enzymes, viz., alkaline phosphatase, acid phosphatase, adenosine monophosphatase and adenosine triphosphatase was studied by histochemical methods in the accessory respiratory organs of two fresh-water fishes (Clarius batrachus and Heteropneustes fossilis). Enzymes have been used as markers to differentiate between functional and non-functional cells of the dendritic organ of Clarius and of the air chamber of Heteropneustes. The variations in the enzyme activities have been correlated with the functional capacity of each respiratory organ. It is attempted to understand the physiological role of these enzymes in the process of aerial breathing.