Profile: Maria (MariVi) Tejada-Simon

Maria Tejada-Simon
Maria Victoria (MariVi) Tejada-Simon, M.Ed., Ph.D.
Assistant Professor of Pharmacology
Joint appointments: Psychology, Biology
Department of Pharmacological and Pharmaceutical Sciences
UH College of Pharmacy
521 Science & Research Bldg. 2
Houston, TX 77204-5037

Office: 713-743-7835
Lab: 713-743-1772
Fax: 713-743-1884


B.S. in Biology, Universidad Complutense de Madrid (Spain)
M.S., Michigan State University, E. Lansing, MI
M.Ed., University of Houston, Houston, TX
Ph.D., Michigan State University, E. Lansing, MI
Postdoctoral Fellowship, Baylor College of Medicine, Houston, TX

Research Interests

  • Small GTPases in LTP, hippocampus-dependent learning and memory.
  • Implication of small GTPases in defective synaptic plasticity.
  • Rac1-dependent regulation of neuronal morphology in cognitive disabilities.


Our research is focused on elucidating the role of the small GTPase Rac in LTP and in hippocampus-dependent learning and memory. In area CA1 of the hippocampus, the most commonly studied form of LTP is dependent on the activation of NMDA receptors. Previously in our laboratory we have found that Rac is highly expressed in the adult mouse hippocampus where it is equally distributed between cytosolic and membrane fractions, indicating that this protein might be cycling between inactive and active forms. In addition, our investigation showed that NMDA receptor activation in hippocampal slices causes Rac to translocate to the membrane in a manner similar to that observed in activated phagocytic cells, and that translocation and activation of Rac occurs during associative contextual fear learning in the hippocampus of the adult animal. We are currently investigating whether Rac is an important molecule involved post-developmentally in synaptic plasticity in the adult mice, playing a role in the neuro-anatomical and cyto-architectural changes of neurons and in the activation of signal transduction pathways associated with LTP and hippocampal learning and memory.

A second aspect of our research is related to mental retardation (MR) syndromes. Precise synaptic connectivity is essential for normal brain function and the most common neuropathology associated with MR is an alteration of this connectivity due to aberrant dendritic spine morphology. Abnormalities in dendrites and spines have been associated with the impaired cognitive abilities in MR, but how they were generated is not yet well understood. It is of great interest to understand the mechanism that lead to lose of synapses and defective synaptic plasticity. In this regard, there is evidence pointing to the Rho family of small GTPases, proteins that mediate actin cytoskeleton reorganization, neuronal morphogenesis and gene expression. The role of the small GTPases-linked genes in MR could provide a connection between the mechanism and the neuronal microstructural deficits observed in these cognitive disorders. Thus, our laboratory is investigating Rac-dependent regulation of neuronal morphology in MR syndromes.

For all these studies we use a multidisciplinary approach, a combination of pharmacological, biochemical, electrophysiological and behavioral studies, coupled with the use of genetically altered mice.

Research Images

Synaptic localization of Rac in the mouse hippocampus. Fig. 2: Electron micrographs of representative sample of synaptoneurosomes isolated from mouse hippocampus. Fig. 3.: Golgi-Cox impregnated neurons from mouse hippocampus.

Lab Members


Luis Martinez Luis Alberto Martinez, B.S. (UH 2004)
Graduate Student (Pharmacology)
Research: Therapeutic approaches in Autism

ray-sucharit.jpg Sucharit Ray
Graduate Student (Biology)
Research: Statins and Autism

stacy-nguy.jpg Stacy Nguy
Undergraduate Student (Biochemistry)
Research: Characterization of fmr1-knockout female mice  

lopez-tenee.jpg Tenee Lopez
Undergraduate Student
Research: Predisposition to schizophrenia in the offsprings of stressed mothers with induced NMDA receptor hypofunction

Lab Alumni

Nadeem Tajuddin, B.S. Medical Sciences      
University of Western Ontario
Summer 2008

Jermeece Augustine Jermeece Augustine, B.S. Biology
University of Houston, Texas
May 2008 – May 2009

Mary Elhardt Mary Elhardt, B.S. Biology and Political Science
University of Houston, Texas
May 2008 – August 2010

Emmanuel Oni, B.S. Biology and Psychology
University of Houston, Texas
May 2009 – May 2010

Karlis Butler, B.S. Pharmaceutical Sciences
University of Houston, Texas
May 2009 – July 2010

AnniePally.jpg Annie Pally, Undergraduate Student (Biochemistry/Honors College)
University of Houston, Texas
January 2011 – December 2011

tina-nguyen.jpg Tina Nguyen, Undergraduate Student (Biochemistry)
University of Houston, Texas
January 2012 – May 2012

Odelia.jpg Odelia Bongmba, Ph.D. in Pharmacology (2012)
University of Houston, Texas
September 2007 – May 2012

tri-le.jpg Tri Le
Undergraduate Student, Biology major with Chemistry and Health minors
September 2012-August 2013
Research: Statins and Autism

Photo Galleries


Laboratory Shots Laboratory Shots Laboratory Shots Laboratory Shots Laboratory Shots Laboratory Shots

Rodent Behavioral Room

Behavioral OFA Behavior Rotarod Behavior Watermaze Behavioral Room NIR Fear Conditioning


January 2013

Graduate student Luis Martinez received a FASEB-MARC award to attend 2013 Experimental Biology conference in April.

February 2013

Dr. Tejada-Simon received a FASEB-MARC faculty/student award to attend EB 2013.

March 2013

Dr. Tejada-Simon was awarded a renewal on her grant with the Jerome Lejeune foundation to continue her studies in Fragile X syndrome.

April 2013

Luis Martinez presented his work “Use of novel pharmacological agents to assess the role of Rho GTPase regulatory proteins in cognition” at Experimental Biology conference held in Boston, MA.

Dr. Tejada-Simon, and students Tri Le and Stacy Nguy attended the 2013 Experimental Biology Annual conference held in Boston, MA, sponsored by a Faculty-student award from FASEB-MARC.

Dr. Tejada-Simon received the inaugural 2013 Faculty Award for Mentoring Undergraduate Research (UH).

Dr. Tejada-Simon has been awarded a GEAR grant (Grants to Enhance and Advance Research) to study the “Therapeutic role of Statins in Autistic disorders.”

May 2013

Biology graduate student Succharit Ray has joined the lab.

August 2013

Dr. Tejada-Simon was awarded a renewal on her grant with the FRAXA Research foundation to continue her studies regarding novel targets and treatment for Fragile X syndrome.

Graduate student, Luis Martinez, presented his work “Use of novel pharmacological agents to assess the role of Rho GTPase regulatory proteins in cognition” at the Graduate Symposium, Department of Pharmacological and Pharmaceutical Sciences.

Senior undergraduate student Tenee Lopez has joined the lab.

September 2013

Luis Martinez, presented his work “Use of novel pharmacological agents to assess the role of Rho GTPase regulatory proteins in Fragile X syndrome” at the Biology of Behavior Institute student Symposium.

Sucharit Ray, presented his work “effect of the inhibition of isoprenylation in the mouse brain” at the Biology of Behavior Institute student symposium.

October 2013

Dr. Tejada-Simon presented “Rac1 inhibition ameliorates observed cognitive deficits in FMRP-deficient female mice” at the SACNAS annual meeting, in San Antonio.

Stacy Nguy presented their research work entitled “Characterization of behavioral deficiencies in Fmr1-knockout female mice” at the Undergraduate Research Day (UH).

Available Positions

We are always looking for research graduate students, research technicians and post-doctoral fellows wishing to help unravel the causes for cognitive impairment, the signaling mechanisms involved and possible therapies to improve the quality of life of these patients. We use a combination of pharmacological, biochemical, electrophysiological and behavioral studies, coupled with the use of genetically altered mice.

Our research is mainly focused on providing important information regarding the signaling mechanisms that underlie synaptic plasticity, learning and memory processes. The consistent abnormality observed in brains of mental retardation subjects is an abnormal morphology of dendritic spines. These investigations might be translated to the basis of diseases involving memory impairment, such as Down syndrome, non-syndromic X-linked mental retardation (MRX), Fragile X mental retardation, Alzheimer’s disease, William’s syndrome, Angelman syndrome (AS), forebrain ischemia, and schizophrenia.

Please send a cover letter, CV, a brief statement of research interests, and contact information to: Dr. Tejada-Simon (

Awards & Honors

  • 2013 Faculty Excellence in Service, College of Pharmacy (UH)
  • 2013 Faculty Award for Mentoring Undergraduate Research (UH)
  • 2013 FASEB MARC Faculty-Student Award 
  • 2012 Provost Faculty travel award
  • 2010 Finalist, Sisley-Jerome LeJeune International Award
  • 2010 FASEB-MARC Faculty-Student Award
  • 2009 Carl Storm Scholarship, Gordon Research Conferences
  • 2009 National Fragile X Foundation Travel Award
  • 2008 Judge Funding Award, Annual Biomedical Research Conference for Minority Students (ABRCMS)
  • 2008 Provost 2008-2009 Faculty Travel Award
  • 2008 MEd Associates Scholarship award
  • 2007 Academy Distinguished Educators Education Scholarship award (BCM)
  • 2007 Biotechnology Institute Fellows Program Award. The Biotechnology Institute.
  • 2006 Academy Distinguished Educators Education Award (BCM)
  • 2005 Neuroscience Scholar Award (NINDS)
  • 2004 National Institute of Neurological Disorders and Stroke (NINDS)
  • 2001 Federation of Clinical Immunology Society Educational Award
  • 2000 Methodist Hospital Foundation Grant Award, Methodist Hospital


Undergraduate courses
PCOL 3396, 4496 – Senior Research Project in Pharmacology
PCOL 3399, 4496 – Honors Thesis in Pharmacology
PharmD courses
PHAR 4400 – Cellular Life Science I
PHAR 5403 – Pharmacology II – CNS, psychosis and antipsychotics
Graduate courses
PCOL 7362 – Neuropharmacology
PCOL 6293, 6298, 6398 – Independent Studies in Pharmacology
PCOL 6370 – Advanced Pharmacology
PCOL 6498 – Special Problems in Pharmacology
PCOL 8300, 8699 – Doctoral Dissertation

Funding & Support

Current Funding
UH Grants to Enhance and Advance Research (GEAR), 2013-14
FRAXA Research Foundation, 2011-2014
Jérôme LeJeune Foundation, 2011-2014

Past Support

The Methodist Hospital Foundation
National Institute of Neurological Disorders and Stroke, NIH
College of Pharmacy, University of Houston
Jérôme LeJeune Foundation
FRAXA Research Foundation
Small Grants Program, University of Houston
National Fragile X Foundation

Selected Publications (since 2005)

Butler, K.; Martinez, L. A.; Tejada-Simon, M.V. (2013). Impaired cognitive function and reduced anxiety-related behavior in a Promyelocytic Leukemia (PML) tumor suppressor protein-deficient mouse. Genes, Brain and Behavior, 12(2):189-202.

Bongmba, O.Y.N.; Tejada-Simon, M.V. (2012). Small GTP-binding proteins as a therapeutic target for cognitive deficiencies. J. Neurol. Neurophysiol., S1:2155-9562.S1.09.

Tejada-Simon, M.V. and Bongmba, O.Y.N. (2012). Regulation of neuronal morphology and plasticity by small GTP-binding proteins: Implications for autism and mental retardation disorders. In Horizons in Neuroscience Research. Volume 8. Chapter 1. Editors: Andres Costa and Eugenio Villalba, NOVA Science Publishers, Hauppauge, NY. ISBN: 978-1-61942-757-0.

Bongmba, O.Y.N.; Martinez, L.A.; Elhardt, M.E.; Butler, K.; Tejada-Simon, M.V. (2011). Modulation of dendritic spine and synaptic function by Rac1: A possible link to Fragile X syndrome pathology. Brain Res. 1399:79-95. Corrigendum in Brain Res.1399 (2011), 79:95. Brain Research, 1423:114-115].

Martinez, L.A.; Tejada-Simon, M.V. (2011). Pharmacological inactivation of the small GTPase Rac1 impairs long-term plasticity and memory in the mouse hippocampus. Neuropharmacol., 61:305-312.

Salim, S.; Sarraj, N.; Taneja, M.; Saha, K.; Tejada-Simon, M.V.; Chugh, G. (2010). Moderate treadmill exercise prevents oxidative stress-induced anxiety-like behaviors in rats. Behav. Brain Res. 208(2):545-552.

Elhardt, M.E.; Martinez, L.A.; Tejada-Simon, M.V. (2010). Neurochemical, behavioral and architectural changes after chronic inactivation of NMDA receptors in mice . Neurosci. Let., 468(2):166-171.

Hoeffer, C.A., Tang, W., Wong, H., Santillan, A., Patterson, R.J., Martinez, L.A., Tejada-Simon, M.V., Paylor, R., Hamilton, S.L., and Klann, E. (2008). Removal of FKBP12 enhances mTOR/Raptor interactions, LTP, memory, and perseverative/repetitive behavior. Neuron, 60(5):832-845.

Tejada-Simon, M.V. (2007). Bringing together the main players on synaptic potentiation. Cell Science, 4(1):37-42.

Martinez, L.A.; Klann, E.; Tejada-Simon, M.V. (2007). Translocation and activation of Rac in the hippocampus during associative contextual fear learning. Neurobiol. Lear. Mem., 88:104-113.

Villasana, L.E.; Klann, E.; Tejada-Simon, M.V. (2006). Rapid isolation of synaptoneurosomes and postsynaptic densities from adult mouse hippocampus. J. Neurosci. Met., 158:30-36.

Tejada-Simon, M.V.; Villasana, L.E.; Serrano, F.; Klann, E. (2006). NMDA receptor activation induces membrane translocation and activation of Rac in mouse hippocampal area CA1 . Biochem. Biophys. Res. Comm., 343(2):504-512.

Tejada-Simon, M.V.; Serrano, F.; Villasana, L.E.; Kanterewicz, B.; Wu, G-Y.; Quinn, M.; Klann, E. (2005). Synaptic localization of a functional NADPH oxidase in the mouse hippocampus. Mol. Cell. Neurosci., 59:97-106.


  • Society for Neuroscience (SFN)
  • American Association of Colleges of Pharmacy (AACP)
  • Soc. Advanc. Chicano & Native Americans in Science (SACNAS)
  • American Society for Neurochemistry (ASN)
  • American Physiology Society (APS)
  • Molecular and Cellular Cognition Society (MCCS)
  • National Hispanic Science Network (NHSN)
  • International Prenylation Society (IPS)
  • Biology of Behavior Institute (BoBI)
  • American Society for Pharmacology and Experimental Therapeutics (ASPET)