title: CART (cocaine- and amphetamine-regulated transcript) peptide specific binding sites in PC12 cells have characteristics of CART peptide receptors.
abstract: CART (cocaine- and amphetamine-regulated transcript) peptide is a neuropeptide with a powerful central anorexigenic effect. Specific CART peptide binding sites, most likely CART peptide receptors, have been found in PC12 cells. This study further characterizes the CART peptide binding sites in PC12 cells. After differentiation to a neuronal phenotype with nerve growth factor, the number of CART peptide binding sites in PC12 cells tripled. Following dexamethasone treatment, which transforms PC12 cells into chromaffin-like cells, the number of CART peptide binding sites substantially decreased. CART peptide did not affect the differentiation or acetylcholinesterase activity of PC12 cells, indicating that CART peptide does not participate in differentiation or neuronal activity. CART peptide increased the phosphorylation of SAPK/JNK (stress-activated protein kinase/c-Jun-amino-terminal kinase) and subsequent c-Jun protein expression. These effects were reversed by SP600125, a specific JNK-kinase inhibitor. CART peptide did not significantly affect ERK (extracellular signal-regulated kinase), CREB (cAMP responsive element binding protein), or p38 phosphorylation and c-Fos protein expression. Central administration of CART peptide into mice also resulted in increased c-Jun positive cells in dorsomedial hypothalamic nucleus and nucleus of the solitary tract, areas involved in food intake regulation. Activation of c-Jun by CART peptide might indicate a possible role of CART peptide in managing stress conditions rather than a role in cell proliferation or differentiation as well as the more complex and/or specific regulation ways by transcription factors in some nuclei involved in food intake regulation. The characteristics of stress that CART peptide potentially mediates should be further studied.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 166 10 Prague, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Nagelová
authors.affiliation: Laboratory of Functional Neuromorphology, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlarska str. 3, 833 06 Bratislava, Slovak Republic; Department of Human and Clinical Pharmacology, University of Veterinary Medicine, Komenskeho 73, 041 81 Kosice, Slovak Republic.
authors.forename: Zdeno
authors.initials: Z
authors.lastname: Pirník
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 166 10 Prague, Czech Republic.
authors.forename: Blanka
authors.initials: B
authors.lastname: Železná
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 166 10 Prague, Czech Republic. Electronic address: maletin@uochb.cas.cz.
authors.forename: Lenka
authors.initials: L
authors.lastname: Maletínská
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009419:Nerve Tissue Proteins / Q000378:metabolism* / Q000494:pharmacology; D016716:PC12 Cells; D051381:Rats; D018000:Receptors, Peptide / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D017552:Solitary Nucleus / Q000187:drug effects / Q000378:metabolism; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
chemical_list: D009419:Nerve Tissue Proteins; D018000:Receptors, Peptide; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; D000110:Acetylcholinesterase
keywords: Binding; CART peptide; Differentiation; PC12 cell; Signaling; c-Jun