Neuromedin N is a potent modulator of dopamine D2 receptor agonist binding in rat neostriatal membranes.
In the concentration range of 1-10 nM, neuromedin N produced a significant concentration-related increase in the Kd values of [3H]L-(-)-N-propylnorapomorphine binding sites in rat neostriatal membranes with a peak action at 10 nM (36% increase versus the control group mean value). The Bmax values were not affected by neuromedin N. Neurotensin at 10 nM induced an increase in the Kd values, which was not affected by a threshold concentration of neuromedin N (0.1 nM). In view of the higher potency of neuromedin N versus neurotensin to modulate neostriatal D2 receptors in contrast to the higher potency of neurotensin versus neuromedin N to bind to the cloned neurotensin receptors, it seems possible that the neuromedin N activated neostriatal neurotensin receptors controlling the D2 receptors represent a distinct subtype of neurotensin receptors.
Li
X M
XM
Department of Histology and Neurobiology, Karolinska Institutet, Stockholm, Sweden.
Finnman
U B
UB
von Euler
G
G
Hedlund
P B
PB
Fuxe
K
K
D000818:Animals; D001058:Apomorphine / Q000031:analogs & derivatives / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D015259:Dopamine Agents / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D017072:Neostriatum / Q000187:drug effects* / Q000378:metabolism; D009496:Neurotensin / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000378:metabolism; D018028:Receptors, Neurotensin; D017981:Receptors, Neurotransmitter / Q000145:classification / Q000187:drug effects / Q000378:metabolism; D013047:Specific Pathogen-Free Organisms
D015259:Dopamine Agents; D010446:Peptide Fragments; D011954:Receptors, Dopamine; D018028:Receptors, Neurotensin; D017981:Receptors, Neurotransmitter; C042090:neuromedin N; D009496:Neurotensin; C009074:N-n-propylnorapomorphine; D001058:Apomorphine