Differential effects of melanin concentrating hormone on the central dopaminergic neurons induced by the cocaine- and amphetamine-regulated transcript peptide.
Stimulatory effects of cocaine- and amphetamine-regulated transcript (CART) peptide on central mesolimbic, nigrostriatal and mesocortical dopaminergic (DA) neurons were examined in female Sprague-Dawley rats. We also determined the different blocking effects of melanin concentrating hormone (MCH) on the stimulation by CART peptide in central DA systems. Intracerebroventricular administration of 1 microg CART peptide (55-102) produced increases in 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the nucleus accumbens (NA) at 15 and 45 min, and in the striatum (ST) at 15 min, but not in the medial prefrontal cortex (MPFC). We found that the agonist of alpha-melanocyte stimulating hormone (alpha-MSH), MT II, at 10 microg had a stimulatory effect on the NA and ST DOPAC levels similar to the CART peptide. In contrast, 1 microg MCH and the antagonist of alpha-MSH, HS014, significantly decreased NA and ST DOPAC levels. However, only MCH prevented the stimulatory effect of CART peptide on DOPAC levels in the NA, but not in the ST. These results indicate that the stimulation of CART peptide on central DA neurons is region-specific, and that this effect can be blocked by MCH but not by the antagonist of alpha-MSH.
Yang
Shu-Chuan
SC
Department of Nursing, Tzu Chi College of Technology, Hualien 970, Taiwan.
Shieh
Kun-Ruey
KR
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism*; D004333:Drug Administration Routes; D005260:Female; D007028:Hypothalamic Hormones / Q000494:pharmacology*; D008543:Melanins / Q000494:pharmacology*; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D010052:Ovariectomy; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000494:pharmacology; D010907:Pituitary Hormones / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044101:Receptors, Melanocortin / Q000819:agonists / Q000037:antagonists & inhibitors; D013997:Time Factors; D000521:alpha-MSH / Q000031:analogs & derivatives* / Q000494:pharmacology; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine; D007028:Hypothalamic Hormones; D008543:Melanins; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D010907:Pituitary Hormones; D044101:Receptors, Melanocortin; D000521:alpha-MSH; C116941:HS014 cyclic peptide; C105974:acetyl-norleucyl(4)-(aspartyl(5)-histidyl(6)-phenylalanyl(7)-arginyl(8)-tryptophyl(9)-lysyl(10))cyclo-alpha-MSH(4-10)amide; C428723:cocaine- and amphetamine-regulated transcript protein (55-102); D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; C019463:melanin-concentrating hormone