title: The C-terminal neurotensin-(8-13) fragment potently modulates rat neostriatal dopamine D2 receptors.
abstract: The effects of neurotensin fragments and of neurotensin itself on the characteristics of neostriatal dopamine D2 agonist binding were studied in competition experiments with dopamine using the D2 antagonist, [3H]raclopride. The biologically active neurotensin-(8-13) fragment, but not the inactive neurotensin-(1-7) fragment, caused a concentration-related increase in the KH and KL values of dopamine with a maximal increase by 110 and 97%, respectively, at 1 nM, while neurotensin-(1-13) only induced such changes at 10 nM. In view of the higher potency and the increased ability of neurotensin-(8-13) versus neurotensin (1-13) to reduce the affinities of the high- and low-affinity states of the neostriatal D2 receptors, the C-terminal neurotensin fragments may be among the endogenous ligands of the neostriatal neurotensin receptors.
authors: Department of Histology and Neurobiology, Karolinska Institutet, Stockholm, Sweden.
authors: X M
authors: XM
authors: Li
authors: G
authors: G
authors: Von Euler
authors: P B
authors: PB
authors: Hedlund
authors: U B
authors: UB
authors: Finnman
authors: K
authors: K
authors: Fuxe
mesh_terms: D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D017072:Neostriatum / Q000187:drug effects* / Q000378:metabolism; D009496:Neurotensin / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D020891:Raclopride; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000187:drug effects* / Q000378:metabolism; D012457:Salicylamides / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D017448:Receptors, Dopamine D2; D012457:Salicylamides; D009496:Neurotensin; D020891:Raclopride; C054381:neurotensin (8-13)