Salivary and Blood Flow Responses to Different Frequency Stimulation of the Cervical Sympathetic Nerve of the Submandibular Gland in the Cat

Jang, Chul Ho; Choi, Tae Wook; Kim, Jin Ok; Lee, Jin Su; Choi, Chang Ik; Kim, Young Ho

Abstract

BACKGROUND AND OBJECTIVES: It has been assumed that salivary glands receive secretory fibers both from parasympathetic and sympathetic nerves. In fact, however, the existence of sympathetic secretory fibers in the cervical sympathetic nerve has not been established yet, because the salivary response to the cervical sympathetic stimulation is variable and short-lasting, and it tends to cease in spite of continued stimulation. This study investigated whether or not the cervical sympathetic nerve contains specific secretory fibers.
MATERIALS AND METHODS
Salivary and blood flow responses to different frequency stimulation of the cervical sympathetic nerve, and often some autonomic drugs administration were observed from the submandibular gland in chloralose-anesthetized cats.
RESULTS
1) Low frequency stimulation (1-2 Hz) of the sympathetic nerve did not evoke salivary outflow and any change of blood flow, whereas high frequency stimulation of the nerve evoked salivary outflow and decrease of blood flow, in which salivary response tended to cease in spite of continued stimulation. 2) The salivary and blood flow responses to high frequency stimulation (20 Hz) of the nerve were not affected by the intravenous administration of propranolol, but were abolished by regitine. 3) Noradrenalin evoked salivary outflow and decreased blood flow which were not affected by the administration of propranolol but were abolished by regitine. 4) Isoproterenol increased blood flow but did not evoke salivary outflow, and the blood flow response was abolished by propranolol.
CONCLUSION
These results suggest that the cervical sympathetic nerve does not contain specific secretory fibers and salivary outflow response to high frequency stimulation of the nerve may be due to either excitation of motor fibers innervating contractile elements of the excretory duct or chemical transmitters released from the vasomotor fibers.