The possible relation between mastication and parotid secretion in the rabbit.

Abstract

SUMMARY1. Salivary flow has been recorded from conscious rabbits during 1 min periods whilst continuously chewing standard laboratory dry pellets or pieces of carrot and, in some animals, a mash of pellets with water. Flow was measured using contact drop recorders or a continuous flow recorder via Polythene tubes permanently inserted into one or both parotid ducts.2. Large variations in flow were obtained with unilateral recordings particularly during dry pellet chewing. Bilateral recordings showed that the flow was always greater on one side than on the other and that dominant secretion alternated from side to side in an apparently random manner.3. Rabbits chew unilaterally. Videotaped recordings of chewing movements showed that the greater secretion was always produced on the chewing side.4. To test the possibility that drying of the oral mucosa, or the prolonged hardness of the pellets may result in higher flow rates in animals with cannulated ducts than would normally be seen in intact animals, water was injected downstream into the mouth through a third cannula. This was inserted in an anterograde direction in the parotid duct on one side. Significant reductions in flow were recorded during dry pellet eating, but not during carrot eating. When animals were fed a soft pellet mash, salivary flow was significantly lower than with dry pellets.5. Recordings have been made from strain gauges attached to the ascending ramus of the mandible. Previous findings that dry pellets produce greater strain than carrots have been confirmed. It has also been shown that less strain is produced with a soft pellet mash. The strain gauge data suggested that a relation exists between masticatory force and parotid salivary flow.6. The results are compatible with the hypothesis that intra-oral mechanoreceptors may be involved in a masticatory-salivary reflex.t Present address:

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.…”

Efecto de las cargas articulares sobre el flujo y pH salival

“…Condiciones experimentales diferentes o un mayor número de sujetos podrían haber entregado cambios más ostensibles, lo que concordaría con estudios previos (16) , los que señalan que el FSE va disminuyendo, asociándose al envío de señales perturbadas por parte de los mecanoreceptores articulares. Esta perturbación en el envió de señales se debe al proceso de masticación, principal estimulo de la saliva estimulada, en ausencia de estímulos gustativos (17) , el que es alterado por las cargas articulares (18) . Un factor clave para la interpretación de los resultados es el papel que podrían jugar los receptores de la mucosa oral, así como las glándulas salivales menores (dispersas por toda la cavidad bucal), manteniendo el equilibrio y un normal volumen de saliva, a pesar de la estimulación anómala de los receptores articulares.…”

Periodontal Mechanoreceptors and Parotid Secretion in Animals and Man

“…The methods used in the animal experiments have previously been reported in detail (Anderson et al, 1985). New Zealand White rabbits underwent a period of training to accustom them to being handled in a busy laboratory and to a standard feeding program.…”