Ontogeny of the hypothermic response to centrally administered neurotensin in rats.

Neurotensin (NT), an endogenous tridecapeptide, when given intracisternally (i.c.) elicits significant hypothermia in a variety of mammals. The present study was designed to test the ability of centrally administered NT to induce a hypothermic effect in rats at different ages. Intracisternally administered NT (10 and 30 microgram) produced a marked dose-dependent hypothermia in rats aged 5, 10, 20, 30 and 60 days. This study confirms and extends the previously reported hypothermic effect of centrally administered NT in the rat and documents the responsiveness of young animals to the peptide.