Peptide derived from insulin with regulatory activity of dopamine transporter.
A nonapeptide derived from the C terminus of the insulin B chain, H(2)N-Arg-Gly-Phe-Phe-Tyr-Thr-Pro-Lys-Ala-COOH, was found to strongly inhibit dopamine (DA) uptake by rat dopamine transporter (DAT) stably expressed in CHO cells (designated D8 cells). The kinetic experiments on D8 cells gave a curve typical of competitive inhibition with an IC(50)=6.9 microM. This inhibitory effect was also confirmed by experiments on striatal synaptosomes. The rat administered with the nonapeptide unilaterally into substantia nigra showed dose-dependent velocity and duration of the round movement contralateral to the nonapeptide-injected side. In addition, the nonapeptide dose-dependently reduced the binding of the tritium-labeled cocaine analog (-)-2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (WIN35,428) to DAT of D8 cells, which suggests that the nonapeptide may inhibit the transport activity of DAT in the way as cocaine does. Meanwhile, the peptide DOI (insulin with 8 amino acid residues deleted at the C terminus of the B chain) shows a significantly stimulating effect on DAT uptake activity in D8 cells. So insulin is proposed as a kind of neuropeptide precursor in the brain and insulin-derived peptides may be involved in the process of regulating the DA system, and these peptides may be developed into new medicines for disorders concerning the DA system such as Parkinson's disease and cocaine addiction.
Liu
Z
Z
Institute of Biochemistry and Cell Biology, Shanghai Institute of Biology Science, Chinese Academy of Sciences, Shanghai, PR China.
Wang
Y
Y
Zhao
W
W
Ding
J
J
Mei
Z
Z
Guo
L
L
Cui
D
D
Fei
J
J
D000613:Aminobutyrates / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003042:Cocaine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006224:Cricetinae; D050483:Dopamine Plasma Membrane Transport Proteins; D050485:GABA Plasma Membrane Transport Proteins; D007328:Insulin / Q000737:chemistry / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D008565:Membrane Proteins / Q000096:biosynthesis; D026901:Membrane Transport Proteins; D008845:Microinjections; D009419:Nerve Tissue Proteins; D027361:Organic Anion Transporters; D010455:Peptides / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050486:Serotonin Plasma Membrane Transport Proteins; D013378:Substantia Nigra / Q000187:drug effects; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
D000613:Aminobutyrates; D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D050485:GABA Plasma Membrane Transport Proteins; D007328:Insulin; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D027361:Organic Anion Transporters; D010455:Peptides; D012333:RNA, Messenger; D011994:Recombinant Proteins; D050486:Serotonin Plasma Membrane Transport Proteins; C493216:Slc6a3 protein, rat; C493232:Slc6a4 protein, rat; C021279:(1R-(exo,exo))-3-(4-fluorophenyl)-8-methyl-8- azabicyclo(3.2.1)octane-2-carboxylic acid, methyl ester; D003042:Cocaine