Absorption Through the Nasal Mucosa of Mice

Abstract

Following the technique of Clark 1 and Olitsky and Cox 2 in their investigation of absorption through the mucosa of the nose, mice were inoculated intranasally with 0.02 cc. of a mixture of equal parts of 10% potassium ferrocyanide and 10% iron and ammonium citrate. 0.01 cc. of the solution was allowed to drop in small droplets on the outside of each nostril, from which position the mouse gradually breathed it into the nose. At 2, 5, 15, and 30 minutes and 1, 2, 3, 4, 6, and 8 hours the mice were sacrificed by decapitation; the whole head was dropped into 10% formalin containing 5% HCl. After 5 or 6 days in this fixative, to allow for complete decalcification, each head was divided down the middle line and, after clearing and embedding, microscopical preparations were made from each side. They were lightly stained with Mayer's carmine and mounted.

As a result of the examination of preparations from 40 mice, 12 each at 2 and 15 minutes and 2 each at the other times, it is possible to state that in mice at least, the whole process has reached its maximum in animals killed at 2 minutes and from then on the picture is one of decreasing amounts of Prussian blue in any tissue of the area examined. The granules are dispersed through the lymphatics, the blood vessels, and the subarachnoid space. Previous investigators 1 , 2 had not examined preparations earlier than one hour.

At 2 minutes the solution is passing through both olfactory and respiratory mucosa. In the former a few granules are seen between the cells but the great majority appear in streams along the receptor fibrils of the olfactory neuron cells and scattered within the cytoplasm of these cells.