Neurotensin effect on Na+, K+-ATPase is CNS area- and membrane-dependent and involves high affinity NT1 receptor.
We have previously shown that peptide neurotensin inhibits cerebral cortex synaptosomal membrane Na+, K+-ATPase, an effect fully prevented by blockade of neurotensin NT1 receptor by antagonist SR 48692. The work was extended to analyze neurotensin effect on Na+, K+-ATPase activity present in other synaptosomal membranes and in CNS myelin and mitochondrial fractions. Results indicated that, besides inhibiting cerebral cortex synaptosomal membrane Na+, K+-ATPase, neurotensin likewise decreased enzyme activity in homologous striatal membranes as well as in a commercial preparation obtained from porcine cerebral cortex. However, the peptide failed to alter either Na+, K+-ATPase activity in cerebellar synaptosomal and myelin membranes or ATPase activity in mitochondrial preparations. Whenever an effect was recorded with the peptide, it was blocked by antagonist SR 48692, indicating the involvement of the high affinity neurotensin receptor (NT1), as well as supporting the contention that, through inhibition of ion transport at synaptic membrane level, neurotensin plays a regulatory role in neurotransmission.
López Ordieres
María Graciela
MG
Instituto de Biología Celular y Neurociencias Prof. E. De Robertis, PROBICENE-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121-Buenos Aires, Argentina.
Rodríguez de Lores Arnaiz
Georgina
G
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008297:Male; D009496:Neurotensin / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013574:Synaptosomes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism
D018040:Receptors, Neurokinin-1; D009496:Neurotensin; D000254:Sodium-Potassium-Exchanging ATPase