Kinase-dependent modification of dendritic excitability after long-term potentiation.
Patterns of presynaptic activity properly timed with postsynaptic action potential output can not only increase the strength of synaptic inputs but can also increase the excitability of dendritic branches of adult CA1 pyramidal neurons. Here, we examined the role of protein kinase A (PKA) and mitogen-activated protein kinase (MAPK) in the enhancement of dendritic excitability that occurs during theta-burst pairing of presynaptic and postsynaptic firing activity. Using dendritic and somatic whole-cell recordings in rat hippocampal slices, we measured the increase in the amplitude of back-propagating action potentials in the apical dendrite that occurs in parallel with long-term potentiation (LTP) of synaptic inputs. We found that inhibition of the MAPK pathway prevents this enhancement of dendritic excitability using either a weak or strong LTP induction protocol, while synaptic LTP can still be induced by the strong protocol. Both forms of plasticity are blocked by inhibition of PKA and occluded by interfering with cAMP degradation, consistent with a PKA-mediated increase in MAPK activity following induction of LTP. This provides a signalling mechanism for plasticity of dendritic excitability that occurs during neuronal activity and demonstrates the necessity of MAPK activation. Furthermore, this study uncovers an additional contribution of kinase activation to plasticity that may occur during learning.
Rosenkranz
J Amiel
JA
Center for Learning and Memory, University of Texas at Austin, Austin, TX, USA. jeremy.rosenkranz@rosalindfranklin.edu
Frick
Andreas
A
Johnston
Daniel
D
D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D003712:Dendrites / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D005419:Flavonoids / Q000494:pharmacology; D066298:In Vitro Techniques; D007858:Learning / Q000502:physiology; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009570:Nitriles / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects
D002070:Butadienes; D002227:Carbazoles; D005419:Flavonoids; D009570:Nitriles; D047428:Protein Kinase Inhibitors; D011758:Pyrroles; C113580:U 0126; C057416:KT 5720; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one