Anxiogenesis induced by nitric oxide synthase inhibition and anxiolytic effect of melanin-concentrating hormone (MCH) in rat brain

• Published in: Peptides (New York, N.Y. : 1980) Vol. 22; no. 7; pp. 1043 - 1047
• Main Authors: Monzón, M.E, Varas, M.M, De Barioglio, S.R
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-07-2001
• Subjects: Amygdala - drug effects; Amygdala - enzymology; Animals; Brain - enzymology; Enzyme Inhibitors - pharmacology; Hippocampus - drug effects; Hippocampus - enzymology; Hypothalamic Hormones - pharmacology; L-NOARG; Male; Maze Learning - drug effects; Melanins - pharmacology; Neovascularization, Pathologic; Nitric Oxide - metabolism; Nitric Oxide Synthase - antagonists & inhibitors; Nitroarginine - pharmacology; Oxygen - metabolism; Pituitary Hormones - pharmacology; Rats; Rats, Wistar; Time Factors
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/S0196-9781(01)00439-9

In this study, the involvement of nitric oxide (NO) in the mechanism of anxiety was investigated. The rats received an intraamygdaline or intrahippocampal injection of the nitric oxide synthase inhibitor, N
G-nitro-l-arginine (L-NOARG), and were then tested in the plus-maze test. L-NOARG induced a decrease in the time spent by rats in the open arms. Conversely, the administration of the melanin-concentrating hormone (MCH) into these structures increased the number of entries into the open arms as well as the time spent on them. MCH injected in rats pretreated with L-NOARG also was able to revert the anxiogenic effects of L-NOARG in amygdala.