[Effect of a corticoliberin (CRF4-6) on the rat heart rate and behavior].

The effects of tripeptide corticoliberin fragment CRF4-6 (Pro-Pro-Ile) on heart rate and behaviour of rats with simultaneous monitoring of these parameters in free-moving animals in their home cage were investigated. Intracerebroventriculary administered CRF4-6 (6, 30, 150 nmol) induces arousal effect increasing the duration of active behaviour, decreasing the duration of passive behaviour and sleep both. At the same time the tripeptide increases the heart rate during sleep, passive and exploratory activity. CRF4-6 (30, 150 nmol) also increases the heart rate in anaesthetised rats. All observed effects of the tripeptide are dose dependent. Taking into account these facts we suggest that CRF4-6 influences behaviour and heart activities independently.