Beta-adrenergic receptors link NO/sGC/PKG signaling to BDNF expression during the consolidation of object recognition long-term memory.

Abstract

The nitric oxide (NO)/soluble guanylyl cyclase (sGC)/protein kinase G (PKG) pathway is important for memory processing, but the identity of its downstream effectors as well as its actual participation in the consolidation of nonaversive declarative long-term memory (LTM) remain unknown. Here, we show that training rats in an object recognition (OR) learning task rapidly increased nitrites/nitrates (NOx) content in the CA1 region of the dorsal hippocampus while posttraining intra-CA1 microinfusion of the neuronal NO synthase (nNOS) inhibitor L-NN hindered OR LTM retention without affecting memory retrieval or other behavioral variables. The amnesic effect of L-NN was not state dependent, was mimicked by the sGC inhibitor LY83583 and the PKG inhibitor KT-5823, and reversed by coinfusion of the NO donor S-nitroso-N-acetylpenicillamine (SNAP) and the PKG activator 8-bromoguanosine 3',5'-cyclic monophosphate (8Br-cGMP). SNAP did not affect the amnesic effect of LY83583 and KT-5823. Conversely, 8Br-cGMP overturned the amnesia induced by LY83583 but not that caused by KT-5823. Intra-CA1 infusion of the beta-adrenergic receptor blocker timolol right after training hindered OR LTM and, although coadministration of noradrenaline reversed the amnesia caused by L-NN, LY83583, and KT5823, the amnesic effect of timolol was unaffected by coinfusion of 8Br-cGMP or SNAP, indicating that hippocampal beta-adrenergic receptors act downstream NO/sGC/PKG signaling. We also found that posttraining intra-CA1 infusion of function-blocking anti-brain-derived neurotrophic factor (BDNF) antibodies hampered OR LTM retention, whereas OR training increased CA1 BDNF levels in a nNOS- and beta-adrenergic receptor-dependent manner. Taken together, our results demonstrate that NO/sGC/PKG signaling in the hippocampus is essential for OR memory consolidation and suggest that beta-adrenergic receptors link the activation of this pathway to BDNF expression during the consolidation of declarative memories.

• Authors: Cristiane R Furini, Janine I Rossato, Lucas L Bitencourt, Jorge H Medina, Iván Izquierdo, Martín Cammarota
• Journal: Hippocampus (Hippocampus) Vol. 20 Issue 5 Pg. 672-83 (May 2010) ISSN: 1098-1063 [Electronic] United States
• PMID: 19533679 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: 2009 Wiley-Liss, Inc.

Chemical References

• Adrenergic beta-Antagonists
• Antibodies
• Brain-Derived Neurotrophic Factor
• Enzyme Inhibitors
• Receptors, Adrenergic, beta
• Nitric Oxide
• Timolol
• Cyclic GMP-Dependent Protein Kinases
• Guanylate Cyclase

Topics

• Adrenergic beta-Antagonists (pharmacology)
• Animals
• Antibodies (pharmacology)
• Behavior, Animal
• Brain-Derived Neurotrophic Factor (immunology, metabolism)
• Cyclic GMP-Dependent Protein Kinases (metabolism)
• Discrimination Learning (physiology)
• Dose-Response Relationship, Drug
• Drug Interactions
• Enzyme Inhibitors (pharmacology)
• Gene Expression Regulation (drug effects, physiology)
• Guanylate Cyclase (metabolism)
• Male
• Nitric Oxide (metabolism)
• Rats
• Rats, Wistar
• Receptors, Adrenergic, beta (physiology)
• Recognition, Psychology (drug effects, physiology)
• Signal Transduction (drug effects, physiology)
• Time Factors
• Timolol (pharmacology)