THE EFFECT OF SECTION OF THE SUPRAOPTICO-HYPO-PHYSEAL TRACTS ON THE INHIBITION OF WATER-DIURESIS EMOTIONAL STRESS

¹ Pharmacology Laboratory, Cambridge

1. Section of the supraoptico-hypophyseal tracts in four dogs resulted in atrophy of the neurohypophysis and a varying degree of diabetes insipidus.

2. After section of the supraoptico-hypophyseal tracts, a greatly reduced amount of antidiuretic substance was released from the neurohypophysis during emotional stress, as was shown by an almost complete abolition of the slow type of inhibition of water-diuresis. The amount of antidiuretic substance released was approximately 5 per cent. of the amount liberated in response to the same stimulus before tract section.

3. There was no difference in the size of the residual inhibition by emotional stress after tract section and after removal of the posterior lobe of the pituitary.

4. The results are discussed in relation to the production of diabetes insipidus by section of the supraoptico-hypophyseal tracts.

I wish to acknowledge the assistance of Mr. E. B. Verney in the operative work of this paper.