We investigated in the present study whether systemic injections of prepro-thyrotropin-releasing-hormone 178-199 (PPTRH 178-199) in postnatal 3-days old rat pups can provide ameliorative effects in a model of anxiety-separation disorder. The pups were individually separated from their mother and placed in a novel environment. PPTRH 178-199-treated animals started exploring the novel environment in a significantly shorter time and elicited significantly less distress vocalizations than control animals. PPTRH 178-199-treated animals also had markedly lower serum adrenocorticotropic hormone and corticosterone compared to control animals. Furthermore, we observed a significant increase in PPTRH 178-199 immunoreactive cell bodies in the hypothalamus of PPTRH 178-199-treated animals compared to controls, suggesting that the peptide crossed the blood-brain barrier. PPTRH 178-199 treatment can help to reduce behavioral and hormonal disturbances associated with anxiety-separation situations.
- Adrenocorticotropic hormone
- Corticotropin release-inhibiting factor
- Exploratory activity
- Paraventricular nucleus
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