Defense reaction elicited by microinjection of Kainic acid in the medial hypothalamus of the rat

RESUMO

In order to localize groups of neurons commanding the defense reaction, a subtoxic dose (66 pmol) of kainic acid was microinjected into the medial hypothalamus of the rat. After drug treatment, the animals were placed inside a shuttle-box for 15 min and the number of midline crossings, rearings and forward leaps was recorded. Autonomic changes such as occurrence of micturition and defectation were also measured. Injection of kainic acid significantly increased locomotion, rearing and micturition, indicating that the medial hypothalamus of the rat contains perikarya/dendrites of neurons integrating the defense reaction