Elsevier

Neuropeptides

Volume 33, Issue 6, December 1999, Pages 468-474
Neuropeptides

Regular Article
Neonatal handling in rats induces long-term effects on dynorphin peptides

https://doi.org/10.1054/npep.1999.0764Get rights and content

Abstract

The effects of neonatal handling on the opioid dynorphin peptides in the brain and pituitary gland of Sprague-Dawley rats were investigated. Ten weeks after the neonatal handling, handled rats had higher tissue levels of dynorphin A and B in the hypothalamus, pituitary gland and striatum and slightly higher dynorphin B levels in the hippocampus, medulla oblongata and midbrain as compared with non-handled controls. The results indicate a persistent upregulation of the dynorphin system in certain brain areas after neonatal handling, which could contribute to the behavioural changes in these rats observed later in life. Observation in the open field and the elevated plus-maze tests confirmed behavioural effects of neonatal handling, i.e. showing that handled rats exhibit attenuated fearfulness in novel environments as compared with non-handled rats.

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