Secretory interactions between the sympathetic and parasympathetic innervations of the submandibular gland in the anaesthetized cat

Abstract

SUMMARYInteractions between the sympathetic and parasympathetic innervations of the submandibular gland have been investigated in the anaesthetized cat. At low frequencies of chorda lingual (parasympathetic) stimulation, simultaneous stimulation of the ascending cervical sympathetic nerve in bursts (20 Hz for 1 s at 10 s intervals) increased the flow of submandibular saliva, but the effect was never more than additive. The output of protein was consistently reduced by simultaneous stimulation of both the sympathetic and parasympathetic innervations, below that evoked by stimulation of either alone. Sympathetic stimulation was more effective than parasympathetic stimulation in promoting the secretion of tissue kallikrein and peroxidase in the submandibular saliva. The output of the latter enzyme, in response to sympathetic stimulation, was significantly reduced by simultaneous stimulation of the parasympathetic innervation at frequencies greater than 1 Hz, but nevertheless exceeded the amount secreted during chorda stimulation alone. Thus, this protocol provided no evidence of synergy between the two divisions of the autonomic nervous system with respect to any submandibular secretory function that was recorded. However, following the administration of a small dose of atropine (2-15 jug kg-' I.V.), sufficient to block secretion during chorda stimulation alone, the flow of saliva, in response to sympathetic stimulation, was potentiated when superimposed on a background of parasympathetic stimulation at all frequencies that were employed. This effect was abolished by larger doses of atropine, indicating that it was dependent upon activation of muscarinic receptors, only some of which could have been blocked by the initial dose.

Implant‐Supported Electrostimulating Device to Treat Xerostomia: A Preliminary Study

“…Since then, electrostimulation of nerves involved in the salivary secretory process has been extensively used in animal experiments. Some of the reported electrical parameters used to excite the nerves are: frequency of 0.1 to 20 Hz, pulse duration of 2 to 5 ms, voltage of 3 to 40 V. [33][34][35][36][37][38][39][40][41][42] Initial human experiments using electrodes attached to a removable dental appliance have shown significant increase in salivation without side effects, even no tingling or discomfort. 43 The impulses that travel through the nerve fibers involved in the salivary reflex follow two directions: the afferent ones go from the sensory organs to the salivary centers in the central nervous system, whereas the efferent fibers are directed from the salivary centers to the salivary glands.…”