PT  - JOURNAL ARTICLE
AU  - Tahar Aboulkassim
AU  - Xin-Kang Tong
AU  - Yiu Chung Tse
AU  - Tak-Pan Wong
AU  - Sang Woo
AU  - Kenneth Neet
AU  - Fouad Brahimi
AU  - Edith Hamel
AU  - H. Uri Saragovi
TI  - Ligand-dependent TrkA activity in brain impacts differently on spatial learning and long-term memory
AID  - 10.1124/mol.111.071332
DP  - 2011 May 26
TA  - Molecular Pharmacology
PG  - mol.111.071332
4099  - http://molpharm.aspetjournals.org/content/early/2011/05/26/mol.111.071332.short
4100  - http://molpharm.aspetjournals.org/content/early/2011/05/26/mol.111.071332.full
AB  - In the CNS, the NGF receptor TrkA is expressed primarily in cholinergic neurons that are implicated in spatial learning and memory, whereas the NGF receptor p75NTR is expressed in many neuronal populations and glia. We asked whether selective TrkA activation may impact differently on learning, short-term memory, and long-term memory. We also asked whether TrkA activation might impact cognition differently in wild type mice versus mice with cognitive deficits due to transgenic over-expression of mutant amyloid-precursor protein (APP mice). Mice were treated with wild type NGF (a ligand of TrkA and p75NTR); or with selective pharmacological agonists of TrkA that do not bind to p75NTR. In APP mice the selective TrkA agonists significantly improved learning and short-term memory. These improvements are associated with a reduction of soluble Aβ levels in the cortex and AKT activation in the cortex and hippocampus. However, this improved phenotype did not translate into improved long-term memory. In normal wild type mice, none of the treatments affected learning or short-term memory; but a TrkA selective agonist caused persistent deficits in long-term memory. The deficit in wild type mice was associated temporally, in the hippocampus, with increased AKT activity, increased pro-BDNF, increased NRH-2 (p75-related protein), and long-term depression. Together, these data indicate that selective TrkA activation impacts on cognition, but does so differently in impaired APP mice versus normal wild type mice. Understanding mechanisms that govern learning and memory is important for better treatment of cognitive disorders.