Histochemical localization of biogenic monoamines in the posterior salivary glands of octopods

Tubules of the octopod posterior salivary gland are lined by two distinct epithelia, type A and B of which type A is predominant. A positive chromaffin reaction is given only by a small proportion of columnar cells of the type A epithelium, and is apparently associated with the large (3mu) cytoplasmic granules of these cells. A similar proportion of type A columnar cells exhibit formaldehyde-specific fluorescence which is not reduced by reserpine in doses which reduced fluorescence in the optic lobes and in fibres associated with myoendothelial cells investing the posterior salivary gland tubules.