Differential cAMP signaling at hippocampal output synapses.

Abstract

cAMP is a critical second messenger involved in synaptic transmission and synaptic plasticity. Here, we show that activation of the adenylyl cyclase by forskolin and application of the cAMP-analog Sp-5,6-DCl-cBIMPS both mimicked and occluded tetanus-induced long-term potentiation (LTP) in subicular bursting neurons, but not in subicular regular firing cells. Furthermore, LTP in bursting cells was inhibited by protein kinase A (PKA) inhibitors Rp-8-CPT-cAMP and H-89. Variations in the degree of EPSC blockade by the low-affinity competitive AMPA receptor-antagonist gamma-d-glutamyl-glycine (gamma-DGG), analysis of the coefficient of variance as well as changes in short-term potentiation suggest an increase of glutamate concentration in the synaptic cleft after expression of LTP. We conclude that presynaptic LTP in bursting cells requires activation of PKA by a calcium-dependent adenylyl cyclase while LTP in regular firing cells is independent of elevated cAMP levels. Our results provide evidence for a differential role of cAMP in LTP at hippocampal output synapses.

• Authors: Christian Wozny, Nikolaus Maier, Pawel Fidzinski, Jörg Breustedt, Joachim Behr, Dietmar Schmitz
• Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci) Vol. 28 Issue 53 Pg. 14358-62 (Dec 31 2008) ISSN: 1529-2401 [Electronic] United States
• PMID: 19118168 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Excitatory Amino Acid Antagonists
• GABA Antagonists
• Isoquinolines
• Oligopeptides
• Protein Kinase Inhibitors
• Pyridazines
• Quinoxalines
• Sulfonamides
• 2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline
• gamma-glutamyl-glycyl-glycine
• 8-chloroadenosine-3',5'-cyclic monophosphorothioate
• Colforsin
• gabazine
• Cyclic AMP
• N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide
• Calcium

Topics

• Action Potentials (drug effects, physiology)
• Analysis of Variance
• Animals
• Calcium (metabolism)
• Colforsin (pharmacology)
• Cyclic AMP (analogs & derivatives, pharmacology, physiology)
• Electric Stimulation
• Excitatory Amino Acid Antagonists (pharmacology)
• Excitatory Postsynaptic Potentials
• GABA Antagonists (pharmacology)
• Hippocampus (cytology)
• In Vitro Techniques
• Isoquinolines (pharmacology)
• Neurons (drug effects, physiology)
• Oligopeptides (pharmacology)
• Patch-Clamp Techniques
• Protein Kinase Inhibitors (pharmacology)
• Pyridazines (pharmacology)
• Quinoxalines (pharmacology)
• Rats
• Signal Transduction (drug effects, physiology)
• Sulfonamides (pharmacology)
• Synapses (drug effects, physiology)
• Time Factors