Intracellular signalling in salt-secreting cells - recent advances in the avian nasal gland model

Abstract

The avian nasal gland has had an important role as a model system in studies of ion secretion for almost forty years, ever since the discovery of its role as an extrarenal salt-secreting organ by Schmidt-Nielsen and colleagues (Fänge et al. 1958). Less widely appreciated is the fact that this tissue also played a critical role in the earliest studies of the intracellular signalling pathways involved in the stimulation of cell activity. Some of the original studies demonstrating for the first time that the muscarinic stimulation of secretory activity in cells was associated with an increased turnover of membrane phosphoinositides were performed on the avian nasal gland (Hokin and Hokin 1964). Unfortunately, the key connection between this turnover of phosphoinositides and increases in cytosolic Ca²⁺ concentrations ([Ca]j) was not appreciated until more than ten years later (Michell 1975), and the role of inositol 1,4,5-trisphosphate in providing the critical link between these two processes was not revealed for a further eight years (Streb et al. 1983).