Stress Factors Can Reverse the Pinealostimulatory Effect of 6-hydroxydopamine on the Pineal Gland of Blossomheaded Parakeet (Psittacula cyanocephala)

A study of the pineal gland of adult male blossomheaded parakeets was conducted with the aid of light microscopic examination to determine the influence of stress on pineal cells. It was demonstrated that stress decreased the growth and activity of the pinel cells when induced as hyperosmolality (water deprivation, salt ingestion). This influence on the pineal gland was not inhibited by previous treatment of a sympatholytic agent, 6-hydroxydopamine.