title: Microinjection of cocaine- and amphetamine-regulated transcript 55-102 peptide into the nucleus accumbens could modulate anxiety-related behavior in rats.
abstract: Cocaine- and amphetamine-regulated transcript (CART) peptide is abundantly expressed in the nucleus accumbens (NAcc) and is involved in stress, anxiety and reward responses. To examine the role of CART peptide in anxiety-related behavior, naïve rats were bilaterally injected with CART 55-102 peptide (0.5, 1.0 or 2.5 µg/0.5 µl/side) or vehicle into the NAcc. Following this, their anxiety-related behavior was assessed using the elevated plus maze and the open field tests with a one-week interval between the tests. There was no difference in the time spent in open arms, or number of entries into open arms on the elevated plus maze in the CART-treated animals at any dose, when compared with the vehicle-treated group. However, there was a significant increase in the time spent in the center of the open field with administration of the low dose of CART peptide (0.5 µg/0.5 µl/side), although this effect disappeared at the high dose (2.5 µg/0.5 µl/side). None of the doses of CART peptide altered total locomotion in these tests. To further determine the possible anxiety-modulating effect of CART peptide at low dosages, the light and dark test was performed. Additional groups of rats given doses of 0.01 µg/0.5 µl/side or 0.5 µg/0.5 µl/side of CART peptide showed increased exploration time in the light side. These results suggest that accumbal-CART peptide reduces anxiety-like behavior in a dose-dependent manner.
authors.affiliation: Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan.
authors.forename: Hyung Shin
authors.initials: HS
authors.lastname: Yoon
authors.affiliation: Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Adachi
authors.affiliation: Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan. Electronic address: hkunugi@ncnp.go.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kunugi
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000008:administration & dosage; D001007:Anxiety / Q000503:physiopathology*; D008297:Male; D008845:Microinjections; D009043:Motor Activity / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000008:administration & dosage / Q000502:physiology*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
chemical_list: D014151:Anti-Anxiety Agents; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C428723:cocaine- and amphetamine-regulated transcript protein (55-102); D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
keywords: Anxiety; Cocaine- and amphetamine-regulated transcript; Elevated plus maze test; Light and dark test; Nucleus accumbens; Open field test