Synergistic autonomic nervous regulation of accelerated salivary gland growth in rats

Abstract

Within 8 days after a submandibular salivary gland is deprived of its parasympathetic nervous innervation, the gland undergoes a marked reduction in weight. After either sympathectomy or parasympathectomy, the increase in gland weight which usually follows incisor amputation or dietary pancreatin is partially inhibited. The gland weight response to these two stimuli is completely inhibited after combined sympathectomy and parasympathectomy. In contrast, the response of the glands to isoproterenol is not dependent upon nervous innervation since administration of the drug still causes glandular enlargement after partial or complete denervation. Compensatory growth of the remaining submandibular gland after removal of one gland and ligation of the ducts of the parotid glands is partially inhibited by section of either nervous branch alone and almost entirely inhibited after complete denervation. A small but definite compensatory response still occurs after complete denervation indicating that humoral as well as nervous factors may be involved in this response. In hypophysectomized rats the response of the submandibular glands to growth hormone administration is not impaired by partial or complete autonomic denervation, indicating that nervous factors do not have a role in this effect of growth hormone.