Abstract

With the chorda tympani cut and the sympathetic supply of the pilocarpinized submaxillary gland of the dog intact, the intravenous injection of sodium sulphide caused variable changes in submaxillary secretion and blood volume flow accompanied by transient stimulation of respiration and sharp fluctuations in blood pressure. With the sympathetic supply to the gland cut also the secretion slowed uniformly when sodium sulphide was administered; submaxillary blood volume flow increased, and the same changes in respiration and blood pressure occurred.

It is suggested that sodium sulphide acts peripherally by virtue of its reducing action and by decreasing the hydrogen ion concentration, but that with the sympathetic intact the peripheral effect was interfered with by a central action.

A small dose of sodium cyanide intravenously produced definite slowing of salivary secretion, a sharp initial increase in submaxillary blood volume flow followed by decreased flow, transient hyperpnea, a rise and then a fall in blood pressure, and depression of the rate of oxygen consumption. These changes were alike in their occurrence whether the sympathetic was intact or not.

The slow intravenous administration of dilute sodium cyanide solution produced an initial decrease in salivary secretion, but later an increase in secretion as with prolonged low oxygen inhalation. It also caused increased submaxillary blood volume flow, persistent hyperpnea, and marked reduction of oxygen consumption.

Depression of oxidations, changes in acid base equilibrium and in blood volume flow, and reduction of carbon dioxide by the hyperpnea probably were all concerned in the effect of cyanide upon salivary secretion.

Methylene blue always increased secretion. The increase developed gradually and was generally preceded by a transient decrease below the initial rate. Usually it increased submaxillary blood volume flow after an initial decrease. It produced hyperpnea, a sharp rise in blood pressure, and an increase in the rate of oxygen consumption. In all these respects the effect persisted for some time. The effects of methylene blue were not modified by the section of the vago-sympathetic.

It is probable that the augmented secretion was dependent mainly upon increased oxygen available to the gland cells. Increased blood flow through the gland, change in acid base equilibrium, and increased temperature may have been contributory factors.