Parotid Saliva Of Sheep Research Articles

Local action of parathyroid hormone (1-34) and (1-84) at the parotid gland of sheep.

Administration of bovine parathyroid hormone (PTH) preparations increased the phosphate concentration in the parotid saliva of sheep. Data on the site of action of PTH (1-84) were obtained by (a) equimolar infusions of PTH (1-84) and (1-34) directly into the arterial blood supply of the vascularly isolated parotid gland in anaesthetized sheep, (b) intravenous infusion of PTH (1-84) at a similar rate and (c) intra-arterial infusion of PTH (1-84) with complete drainage of the venous effluent from the gland during the infusion. Results showed substantial time- and dose-response identity of the two peptides, at 10(-9) to 4 X 10(-9) mol/l in arterial blood, in raising salivary phosphate concentration. The effect of PTH (1-84) was not due to recirculated fragments because the response was obtained when recirculation was prevented by complete venous drainage and little or no response occurred when the same infusion was given i.v.

Parotid saliva of sheep. 1. Effects of level of intake and type of roughage

In three experiments, quantitative collections of saliva were made from the right parotid duct of six Merino wethers. Experiment 1 assessed the repeatability of the collection techniques and found little difference in salivary parameters measured at intervals over a 6-week period. When chopped lucerne was given at three levels (experiment 2) the secretion rate of parotid saliva (g 19.5h-1) increased (P < 0.01) with increasing lucerne consumption as did the concentrations and amounts of total and urea nitrogen in saliva (P < 0.05 to P< 0.01). Only minor changes in the secretion of total and reducible sulfur occurred. Plasma urea nitrogen (P < 0.05) and blood sulfate sulfur (P < 0.01) concentrations increased with increasing lucerne consumption. Values are given to indicate the variability between sheep in volume and composition of parotid saliva secretions. In experiment 3 the sheep were offered four different roughage diets. The secretion rate of saliva (g 19.5h-1) increased (P < 0.01) when more fibrous roughages were given. The type of roughage also affected (P < 0.01) the concentrations and amounts of total and urea nitrogen in saliva, but there was little effect upon the secretion of total or reducible sulfur. Plasma urea nitrogen and blood sulfate sulfur concentrations were different (P < 0.01) on the various roughage diets. The results are compared with the findings of previous research, and estimates of the amounts of nitrogen and sulfur recycled to the rumen in saliva are made.

The effect of carbonic anhydrase inhibitors on the anionic composition of sheep's parotid saliva. With an appendix on uncatalysed carbon dioxide-water kinetics by P. T. McTigue.

1. The effects of the carbonic anhydrase inhibitors, acetazolamide, ethoxzolamide and benzolamide on the ionic composition of parotid saliva were studied in anaesthetized sheep with access to the parotid blood vessels. 2. The inhibitors were infused directly into the arterial blood supply to the gland to give blood concentrations in the range 10(-5) to 10(-2) M. 3. Mean anionic concentrations at basal flow rate before inhibitor infusion were, bicarbonate 98 m-mole/l., phosphate 15 m-mole/l. and chloride 26 m-mole/l. In the presence of inhibitors, bicarbonate concentration fell by 11 m-mole/ml. and phosphate and chloride concentrations rose. Secreto-motor nerve stimulation increased bicarbonate concentration by 13 m-mole/l. before infusion of inhibitors and the concentrations of the other anions fell. The bicarbonate rise was abolished by the inhibitors and the fall in phosphate concentration was balanced by a rise in chloride concentration. 4. These effects show that only a small component of the bicarbonate ion transfer system in the sheep parotid gland is sensitive to these inhibitors. 5. The relationship of these findings to a new enzyme with carbonic anhydrase action isolated from the sheep's parotid gland is discussed.

Increased water drinking induced by sodium depletion in sheep.

Forty-eight hours of sodium depletion by acute cannulation of a parotid duct, via the buccal papilla, in the sheep, resulted in a progressive decrease in salivary secretion rate, salivary, urinary and plasma [Na] and no change in plasma [K]. In the first 24 h of Na depletion water intake was significantly increased. As normal sheep parotid saliva [Na] is higher than plasma [Na] and salivary loss over the first 24 h represented Na loss in excess of water relative to extracellular proportions, increased water intake was not osmotically induced. However, the animals did not replace their water deficit on either of the 2 days of Na depletion. This would appear to be valuable experimental model of increased water intake probably induced by hypovaolaemia, but uncomplicated concurrent osmotic stimuli, or any other factors which might result with the other commonly used experimental stimuli of thirst such as haemorrhage.

IgA in the Body Fluids of Sheep and Cattle

A monospecific anti-sheep IgA serum has been used to demonstrate the presence of IgA in most of the mucous secretions {whey, non-parotid saliva, nasal, lung and vaginal washings, bile, oviductal and ovarian follicular fluid and seminal plasma) and in blood serum of sheep. Failure to detect IgA in parotid saliva of sheep was consistent with the virtual absence from the parotid gland of cells of the lymphocyte-plasma cell series. IgA was detected in significant quantities in non-parotid saliva which correlated with the finding of numerous pyroninophilic cells in inter-alveolar areas of the sub-maxillary salivary gland. Monospecific anti-sheep IgA cross reacted strongly with IgA in whey [from an immunized gland) and serum of cattle. On this basis it was possible to detect IgA in other mucous secretions (nasal, intestinal and vaginal washings, bile and mixed saliva) of cattle. IgA could be detected in ovine and bovine urine and ovine parotid saliva after concentrating 700-1000-fold.

SECRETION OF MAGNESIUM AND CALCIUM IN PAROTID SALIVA OF SHEEP.

WITH a conscious sheep, Kay1 confirmed the findings of Coats and Wright2, obtained with anaesthetized sheep, that the concentration of Na+ and K+ in parotid saliva showed a strong inverse correlation. However, neither author reported the saliva concentrations of Mg2+ and Ca2+. McDougall3 estimated the average magnesium concentration in parotid saliva of sheep as 0.6 m.equiv./l. and that of calcium as 0.4 m.equiv./l. Average values of 0.36 and 0.33 m.equiv./l. for saliva magnesium and calcium concentrations, respectively, were obtained here.