Date of this Version
Published in Transactions of the Nebraska Academy of Sciences, Volume 1 (1972).
It has been realized since Ludwig's original studies that the mechanisms which underlay the secretion of saliva involve some type of active process in the gland (Ludwig et al., 1851). It was demonstrated in those early experiments that the submaxillary ductal pressure in dogs will rise above arterial pressure when the duct is occluded during active secretion. Since then, experiments carried out in a wide range of epithelial tissues which are capable of transcellular transfer of large volumes of fluid and electrolytes (e.g., frog skin, toad bladder, gall bladder, small intestine, etc.) have provided ample evidence that water transport through cells is associated with active electrolyte transport (e.g. see Diamond's extensive treatment of this subject; Diamond, 1964). Thus, it seems reasonable to suspect that the fluid generating mechanism in salivary glands is associated with electrolyte secretion. However, there have been few efforts to examine relationships between electrolyte secretion rates and fluid generation at multiple physiological levels of function of the glands. Thaysen et al. (1954) reported on Na, K, Cl, and CO2 in human parotid saliva in a study whereby stimulation was provided by acetylcholine administration, and Yoshimura, et at. (1963) have investigated the same electrolytes in human mixed saliva under resting conditions and during pilocarpine administration.
The study described below was done using human parotid secretions; it was designed to define the relationships between the rates of secretion of sodium, potassium and chloride fluid secretion rates, and to the osmolality of the secretory fluid under differing degrees of gland function. While the data have been reported elsewhere (Suddick and Shannon, 1970), this paper provides the opportunity to offer a theory of secretory cell transport processes which could explain the reported results, and which may provide some new insights into exocrine secretory processes.