A link between maze learning and hippocampal expression of neuroleukin and its receptor gp78.
Neuroleukin (NLK) is a multifunctional protein involved in neuronal growth and survival, cell motility and differentiation, and glucose metabolism. We report herein that hippocampal expression of NLK and its receptor gp78 is associated with maze learning in rats. First, mRNA levels of NLK and gp78 were significantly increased in hippocampi of male Fischer-344 rats following training in the Stone T-maze and the Morris water maze. Second, a parallel increase was found in hippocampal NLK and gp78 proteins after maze learning. Third, NLK and gp78 mRNA and protein expression in hippocampus was reduced in a group of aged rats that showed more errors during the acquisition of the Stone maze task as compared with young rats. Finally, application of recombinant NLK to hippocampal neurons significantly enhanced glutamate-induced ion currents, functional molecular changes that have been correlated with learning in vivo. Taken together, our results identify a novel association of hippocampal expression of NLK and its receptor gp78 with rat maze learning. Interaction of NLK with gp78 and subsequent signaling may strengthen synaptic mechanisms underlying learning and memory formation.
Luo
Yongquan
Y
Laboratory of Immunology, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA.
Long
Jeffery M
JM
Lu
Chengbiao
C
Chan
Sic L
SL
Spangler
Edward L
EL
Mascarucci
Paolo
P
Raz
Avraham
A
Longo
Dan L
DL
Mattson
Mark P
MP
Ingram
Donald K
DK
Weng
Nan-Ping
NP
D000375:Aging / Q000502:physiology; D000818:Animals; D015870:Gene Expression / Q000502:physiology; D005956:Glucose-6-Phosphate Isomerase / Q000235:genetics*; D018698:Glutamic Acid / Q000494:pharmacology; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D011916:Rats, Inbred F344; D060285:Receptors, Autocrine Motility Factor; D018121:Receptors, Cytokine / Q000235:genetics*; D011986:Receptors, Somatotropin / Q000235:genetics*; D044767:Ubiquitin-Protein Ligases
D018121:Receptors, Cytokine; D011986:Receptors, Somatotropin; D018698:Glutamic Acid; D060285:Receptors, Autocrine Motility Factor; D044767:Ubiquitin-Protein Ligases; D005956:Glucose-6-Phosphate Isomerase