Studies on the pharmacological properties of oxindole (2-hydroxyindole) and 5-hydroxyindole: are they involved in hepatic encephalopathy?

In view of the potent pharmacological effects observed after oxindole or 5-hydroxyindole administration, we thought it important to clarify: 1) the behavioral effects and the pharmacological properties of these indole derivatives; 2) whether or not such neuro-active molecules are present in mammalian tissues; 3) whether or not they accumulate in the course of hepatic encephalopathy; 4) what the mechanism is of their pharmacological actions. We report here a series of preliminary results on these issues. Unfortunately, the basic mechanism of the phamlacological action of oxindole and of 5-0H-indole remains to be clarified.