A tropomyosin-related kinase B ligand is required for ERK activation, long-term synaptic facilitation, and long-term memory in aplysia.
BDNF, which acts through tropomyosin-related kinase B (TrkB) receptors during mammalian development, also enhances long-term synaptic facilitation (LTF) in adult Aplysia. Because LTF is a substrate for long-term memory (LTM) in Aplysia, we examined the requirement of a secreted TrkB ligand in LTM formation at molecular, synaptic, and behavioral levels. Using an extracellular fusion protein that sequesters secreted TrkB ligands, we show that TrkB function is required for serotonin-induced activation of extracellular signal-regulated kinase, tail nerve shock-induced LTF in the CNS, and tail shock-induced LTM but is not necessary for short-term synaptic facilitation or short-term memory. These results show that a secreted growth factor, acting through a TrkB signaling cascade, is critical for the induction of long-lasting plasticity and memory formation in Aplysia.
Sharma
Shiv K
SK
Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA 92697, USA.
Sherff
Carolyn M
CM
Stough
Shara
S
Hsuan
Vickie
V
Carew
Thomas J
TJ
D000818:Animals; D001048:Aplysia / Q000033:anatomy & histology / Q000502:physiology; D001522:Behavior, Animal / Q000502:physiology; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D004558:Electric Stimulation; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008024:Ligands; D017774:Long-Term Potentiation / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D020813:Receptor, trkB / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013569:Synapses / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology
D019208:Brain-Derived Neurotrophic Factor; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D012701:Serotonin; D020813:Receptor, trkB; D048049:Extracellular Signal-Regulated MAP Kinases