Local difference in concentration of vasopressin and monoamines in the equine median eminence.

The hypophysial stalk of the horse had a typical structure of the median eminence and contained noradrenaline, dopamine, serotonin, vasopressin and paraldehyde fuchsine-stainable material. The posterior wall of the hypophysial stalk contained higher concentration of noradrenaline than the anterior and lateral walls. On the other hand, the anterior and lateral walls contained dopamine but the posterior wall did not. The concentration of serotonin was almost the same through these three portions. Vasopressin