The action of orexin A on passive avoidance learning. Involvement of transmitters

• Published in: Regulatory peptides 2002-03, Vol.104 (1), p.105-110
• Main Authors: Telegdy, G, Adamik, A
• Format: Article
• Language: English
• Subjects: Adrenergic alpha-Antagonists - pharmacology; Adrenergic beta-Antagonists - pharmacology; Animals; Atropine - pharmacology; Avoidance Learning - drug effects; Avoidance Learning - physiology; Bicuculline - pharmacology; Carrier Proteins - antagonists & inhibitors; Carrier Proteins - pharmacology; Dopamine Antagonists - pharmacology; Dose-Response Relationship, Drug; Drug Interactions; Enzyme Inhibitors - pharmacology; GABA Antagonists - pharmacology; Haloperidol - pharmacology; Injections, Intraventricular - methods; Intracellular Signaling Peptides and Proteins; Male; Muscarinic Antagonists - pharmacology; Naloxone - pharmacology; Narcotic Antagonists - pharmacology; Neuropeptides - antagonists & inhibitors; Neuropeptides - pharmacology; Neurotransmitter Agents - physiology; Nitric Oxide Synthase - antagonists & inhibitors; Orexin A; Orexins; Passive avoidance learning; Phenoxybenzamine - pharmacology; Propranolol - pharmacology; Rats; Rats, Wistar; Transmitters
• ISSN: 0167-0115; 1873-1686
• DOI: 10.1016/S0167-0115(01)00341-X

The action of orexin A on one-way passive avoidance learning was studied in rats. Orexin A administered into the lateral brain ventricle in conscious rats facilitated learning, the consolidation of learning and also retrieval processes in a dose-dependent manner in a passive avoidance paradigm. The involvement of transmitters was studied by pretreating the animals with receptor antagonists, which had proved to be effective with other neuropeptides in attenuating or blocking the action of orexin A. The following receptor blockers were used: haloperidol, phenoxybenzamine, propranolol, atropine, bicuculline, naloxone and nitro- l-arginine, which can block nitric oxide synthase. In the doses used all of the receptor blockers attenuated, but none of them fully blocked the action of orexin A on the consolidation of passive avoidance learning. The results demonstrate that orexin A is able to facilitate learning, consolidation of learning and also retrieval processes in a passive avoidance paradigm. A number of transmitters could be involved in the action of consolidation, but none of them is absolutely essential.