SUMMARYThe central nucleus of the amygdala (CeA) is known to be involved in the regulation of autonomic, neuroendocrine, and behavioural responses in stress situations. The CeA contains large numbers of corticotropin-releasing hormone (CRH)-containing cell bodies and terminals. In the present study we examined (by continuous behaviour observations) the effects of a high close of CRH (150 rig) and two doses of the CRH-receptor antagonist (a-hCRH: 1.0 and 0.1 p,g) after microinfusion into the CeA in freely moving male Wistar rats under stress-flee conditions. In comparison with control, a-hCRH infusion did not cause any behavioural activation. In contrast CRH-infusion revealed a long-lasting increase in grooming and exploration with a concomitant decrease in behaviours specified as resting. These results indicate that the CRH system in the CeA does not seem to be activated in stress-free conditions, but its activation is of importance for active behavioural responses.Keywords--Central nucleus of the amygdala (CeA); Stress-free conditions; Corticotropin-releasing hormone (CRH); a-Helical CRH (CRH-receptor antagonist).

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