Β‐adrenergic Effects on Composition of Parotid Salivary Secretion of Sheep on Feeding

Abstract

SUMMARYObservations were made in sheep, before and after fresh food was given during teasing with food and after rumination, on the flow of parotid saliva and its protein, Mg2+, K+, Na+ and Cl-concentrations. The animals studied had either a cannulated or fistulated parotid salivary duct. Parotid salivary flow, protein, Mg2+, K+ and Cl-increased markedly following feeding. The increases in protein and Mg2+, but not in flow, were largely blocked by the I.V. administration of propranolol (1 mg. kg-'). Whereas the actual ingestion offood was associated with large increases in protein (up to 42 5 times, to as high as 1760 ,ug. ml-' of saliva), teasing with food caused relatively minor increases in parotid saliva. There were slight, if any, changes in protein concentration during the increased parotid salivary flows of rumination, whether chewing was on the same side or contralateral to the cannulated parotid salivary duct. It is concluded that a ,J-adrenergic mechanism previously demonstrated in acute experiments contributes to increases in the secretion of protein of the parotid saliva when sheep eat. There was a close correlation between the concentrations of protein and of Mg2+ but not of the other electrolytes studied.

The Possible Role of Periodontal Mechanoreceptors in the Control of Parotid Secretion in Man

“…The parotid secretions in horses and mules (Colin, 1854), sheep (Patterson et al 1982) and rabbits (Anderson et al 1985) are directly related to the chewing side. Electromyographic evidence from Weijs & de Jongh (1977) indicates that there is very little difference in muscle activity between the chewing and non-chewing sides, which was confirmed by Weijs & Dantuma (1981) who reported that there were no differences between the average e.m.g.…”

“…Colin (1854) in the horse and mule, and Patterson, Brightling & Titchen (1982) in the sheep showed that parotid flow in response to chewing was greater on the chewing side than on the contralateral side. Anderson, Hector & Linden (1985) confirmed earlier work (Gj6rstrup, 1980) that rabbits produced greater amounts of parotid saliva during feeding on standard laboratory pellets than feeding on carrot and went on to demonstrate that the flow in response to chewing was always greater on the chewing side than on the contralateral side.…”

Atropine‐resistant Secretory Responses of the Ovine Parotid Gland to Reflex and Direct Parasympathetic Stimulation

“…Patterson, Brightling & Titchen (1982) attached physiological significance to this by showing that a ,J-adrenergic mechanism contributes to increased protein in parotid salivary secretion when sheep first eat. However, there is evidence that this mechanism is not the only one that contributes to export of protein.…”

“…However, there is evidence that this mechanism is not the only one that contributes to export of protein. The /3-adrenergic antagonist propranolol only reduces, and does not eliminate, the protein increases which accompany eating (Patterson et al 1982) as does chronic surgical sympathectomy (Carr, Davey & Titchen, 1984). In the experiments reported here attention has been given to the role that the parasympathetic innervation may have in control of secretion of protein from the ovine parotid gland, especially that mediated by non-cholinergic transmitters.…”

Proceedings of the Physiological Society, 12‐14 September 1985, Cambridge Meeting: Communications

“…With patterned breathing, SV oscillations were always discernible (range 7-61 00) and appeared to reflect pleural pressure swings, but were modulated by the degree of sinus arrhythmia present. (Patterson, Brightling & Titchen, 1982) and superior cervical sympathetic ganglionectomy (Carr, Davey & Titchen, 1984). In the experiments referred to here, stimulation of protein secretion from the parotid other than via the cervical sympathetic innervation and after atropine has been examined.…”