Structure of the Secretory Portion of Calliphora Salivary Glands

Abstract

There has been much interest in the morphogenesis of the protein secretions of insect salivary glands. However, little is known about how the watery component of the saliva is produced. We have studied this aspect of secretion in Calliphora erythrocephala, an insect which apparently produces only one salivary enzyme, amylase. In vitro preparations of the abdominal portions of the paired salivary glands of this insect secrete fluid slowly. Addition of 5-hydroxytryptamine (1 x 10-9 M) to the bathing medium causes a 60-fold increase in the secretion rate. The secreted fluid is high in K and low in Na compared to the bathing medium.