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Graduate Biomedical Sciences Affiliations
Cell, Molecular, & Developmental Biology 
Integrative Biomedical Sciences 
Medical Scientist Training Program 
Neuroscience 
Neuroscience Graduate Program 
Neurosciences 

Biographical Sketch 
Dr. Lori McMahon, Professor, received her B.A., summa cum laude in Biology/Chemistry from Southern Illinois University at Edwardsville and her Ph.D. from Saint Louis University Health Sciences Center in St. Louis, Missouri. Dr. McMahon obtained postdoctoral training at Duke University Medical Center in the Department of Neurobiology and, in 1998, joined the faculty of UAB as an Assistant Professor in the Department of Physiology and Biophysics. She is currently the Jarman F. Lowder Professor of Neuroscience and Director of the UAB Comprehensive Neuroscience Center.

Society Memberships
Organization Name Position Held Org Link
Society for Neuroscience     
 

Research/Clinical Interest
Title
Synaptic plasticity and hippocampal dependent learning
Description
My laboratory has three major areas of investigation: First, we are investigating the mechanisms by which muscarinic and adrenergic receptors modulate synaptic function and plasticity in hippocampus and visual cortex. Specifically, we are examining the molecular mechanisms that underlie a form of long-term depression (LTD) at glutamate synapses that is induced by activation of M1 muscarinic or alpha1 adrenergic receptors and how this synaptic mechanism interacts with other well-characterized forms of long-term plasticity. In addition, we are pursuing the consequences of lesion of the cholinergic and adrenergic inputs to hippocampus and visual cortex on the ability of synapses to express plasticity. Degeneration of cholinergic and adrenergic innervation that occurs in neurodegenerative diseases and aging is known to cause cognitive deficits, thus determining how synaptic function is altered following loss of these inputs could have significant clinical benefit. These studies employ electrophysiology in brain slices and cellular techniques including immunohistochemistry and western blot analysis. In a second project, we are pursuing the effects of estradiol on hippocampal synapse density and synaptic transmission and plasticity. Elevated circulating levels of estradiol enhance memory performance and alterations in hippocampal function are likely to be causally related. We are particularly interested in determining how loss of estradiol during aging impacts hippocampal function and whether hormone replacement therapy can activate estradiol-dependent mechanisms to restore normal hippocampal function and thus learning and memory. Ovariectomized female rats treated with estradiol at various intervals following ovariectomy are used as a model system. Experiments involve electrophysiological measurements of NMDA currents, synaptic transmission, and long-term plasticity in acute brain slices. Determining how estradiol and hormone replacement affects hippocampal function could lead to development of therapies to alleviate hormone-dependent memory loss in aging. In a related project, we are investigating the role of estrogen in major depressive disorder to determine if estrogen replacement can alleviate depressive symptoms in menopause. In a third project, we are investigating the role of protein O-GlcNAcylation on synaptic function and learning in rat hippocampus. Protein O-GlcNAcylation is a metabolically modulated post-translational modification whereby the monosaccharide ß-N-acetyl-glucosamine (O-GlcNAc) is attached in an o-linked fashion to serine or threonine residues of cytoplasmic or nuclear proteins. This modification is under the control of two enzymes that are highly expressed in hippocampus. O-GlcNAcylation of serine/Threonine residues is a tightly regulated process that can be thought of as analogous to phosphorylation. In Alzheimer’s disease, O-GlcNAcylation is decreased, contributing to a pathological increase in phosphorylation of Tau, which may be a contributing factor to the development of neurofibrillary tangles. In diabetes, O-GlcNAcylation is pathologically increased, which could be causal to the deficits in LTP and learning in animal models of diabetes. Thus, we are testing the hypothesis that O-GlcNAcylation of nuclear and cytoplasmic synaptic proteins is a novel, powerful regulator of acquisition and consolidation of new memories dependent upon hippocampal synaptic modification. We employ electrophysiological recordings of neurons in acutely prepared brain slices combined with behavioral assays, pharmacology, biochemistry, morphology and immunohistochemistry to pursue our goals.

Selected Publications 
Bredemann TM, McMahon LL. 17Beta Estradiol increases resilience and improves hippocampal synaptic function in helpless ovariectomized rats. Psychoneuroendocrinology. 2014 Apr;42:77-88. doi: 10.1016/j.psyneuen.2014.01.004. Epub 2014 Jan 17.  24636504 
Taylor EW, Wang K, Nelson AR, Bredemann TM, Fraser KB, Clinton SM, Puckett R, Marchase RB, Chatham JC, McMahon LL. O-GlcNAcylation of AMPA receptor GluA2 is associated with a novel form of long-term depression at hippocampal synapses. J Neurosci. 2014 Jan 1;34(1):10-21. doi: 10.1523/JNEUROSCI.4761-12.2014.  24381264 
Noradrenergic Sympathetic Sprouting and Cholinergic Reinnervation Maintains Non-Amyloidogenic Processing of ABetaPP.
Nelson AR, Kolasa K, McMahon LL. J Alzheimers Dis. 2014 Jan 1;38(4):867-79. doi: 10.3233/JAD-130608.
 		 24081376 
Glycogen Synthase Kinase-3 Inhibitors Reverse Deficits in Long-term Potentiation and Cognition in Fragile X Mice.
Franklin AV, King MK, Palomo V, Martinez A, McMahon LL, Jope RS. Biol Psychiatry. 2013 Sep 13. pii: S0006-3223(13)00731-2. doi: 10.1016/j.biopsych. 2013.08.003. [Epub ahead of print]
 		 24041505 
Estradiol-induced increase in novel object recognition requires hippocampal NR2B-containing NMDA receptors.
Vedder LC, Smith CC, Flannigan AE, McMahon LL. Hippocampus. 2013 Jan;23(1):108-15. doi: 10.1002/hipo.22068. Epub 2012 Sep 11. 		 22965452 
G9a/GLP histone lysine dimethyltransferase complex activity in the hippocampus and the entorhinal cortex is required for gene activation and silencing during memory consolidation. Gupta-Agarwal S, Franklin AV, Deramus T, Wheelock M, Davis RL, McMahon LL, Lubin FD.
J Neurosci. 2012 Apr 18;32(16):5440-53. doi: 10.1523/JNEUROSCI.0147-12.2012. 		 22514307 
Simvastatin-mediated enhancement of long-term potentiation is driven by farnesyl-pyrophosphate depletion and inhibition of farnesylation.
Mans RA, McMahon LL, Li L. Neuroscience. 2012 Jan 27;202:1-9. doi: 10.1016/j.neuroscience.2011.12.007. Epub 2011 Dec 13. 		 22192838 
Smith CC*, Vedder LC*, Nelson AR, Bredemann TM, and McMahon LL. Duration of Estrogen Deprivation, Not Chronological Age, Prevents Estrogen’s Ability to Enhance Hippocampal Synaptic Physiology, Proc Natl Acad Sci USA Nov 9, 2010;107(45):19543-8. Epub 2010 Oct 25.   20974957 
McCoy PA and McMahon LL (2010) Sympathetic sprouting in visual cortex stimulated by cholinergic denervation rescues expression of two forms of long-term depression at layer 2/3 synapses Neuroscience 14;168(3):591-604. Epub 2010 Apr 20 PMCID: PMC2892789  20412838 
McCoy PA, Norton TT, and McMahon LL. Layer 2/3 synapses in the monocular and binocular regions of tree shrew visual cortex express muscarinic receptor dependent long-term depression and long-term potentiation. J. Neurophys. 2008 100(1):336-45.  18480372 
Coactivation of M(1) muscarinic and alpha1 adrenergic receptors stimulates extracellular signal-regulated protein kinase and induces long-term depression at CA3-CA1 synapses in rat hippocampus. Scheiderer CL, Smith CC, McCutchen E, McCoy PA, Thacker EE, Kolasa K, Dobrunz LE, McMahon LL. J Neurosci. 2008 May 14;28(20):5350-8. doi: 10.1523/JNEUROSCI.5058-06.   18480291  
McCoy PA and McMahon LL. Muscarinic Receptor Dependent Long Term Depression in Rat Visual Cortex is PKC Independent but Requires ERK 1/2 Activation and Protein Synthesis J. Neurophys., 98:1862-70 2007.  17634336 
 

Keywords
hippocampus, learning, memory, acetylcholine, Alzheimer's disease, estrogen, NMDA receptors, glycine receptors