Ph.D., University of Cincinnati, 1994
Phone (787)764-0000 ext. 2712
Fax: (787) 764-3875
Field of Interest: Molecular and Cellular Biology of Learning and Memory
Research Interests: The research in my laboratory is dedicated to the understanding of
the neural basis of cognitive function and dysfunction. The research is multidisciplinary
as we intend to gain understanding of the cellular and molecular events that subserve
associative processes in the brain related to the acquisition and storage of information.
Our work has relevance to the future treatment and prevention of neuropsychiatric
illnesses such as Alzheimers disease, Post Traumatic Stress Disorder and
Behavioral Neuroscience Background: We are using the holeboard spatial
discrimination task as a model for associative processes related to learning, memory,
motivation. This task is dependent on the hippocampus, the ventral tegmentum, and the
nucleus accumbens, all structures of the limbic system. The hippocampus is the site in the
brain in which declarative memory is initially stored and processed until it is
transferred to long-term memory stores in the brain. The ventral tegmentum contains
dopaminergic neurons that send projections to other structures in the limbic system,
including the hippocampus, the amygdala, and the nucleus accumbens. An impaired function
of the ventral tegmentum has been postulated for schizophrenia. Projection from the
nucleus accumbens to the hippocampus are thought to contribute a motivational component to
the acquisition of the holeboard search task. We are also utilizing a complex environment
paradigms in which animals are placed within standard or enriched conditions immediately
after weaning. The enriched environment includes toys, tunnels, and a round wheel. We are
also studying molecular biological aspects of emotional memory with the fear conditioning
and the conditioned taste aversion paradigms.
Molecular Neurobiology Background: Information is thought to be stored in the brain as
changes in synaptic strength and structure. The activation of intracellular protein
kinases, such as the cAMP-dependent protein kinase (PKA) and protein kinase C (PKC), and
the subsequent activation of the transcription factor cAMP-Responsive Element Binding
Protein (CREB) are pivotal steps for the formation of long-term memory in several neural
substrates, including the hippocampus and the amygdala. A main goal in our laboratory is
to understand the changes in gene expression that occur during acquisition of the
holeboard task. Approaches used in the laboratory to evaluate this problem include many of
the conventional techniques available for analysis gene expression, such as Northen
blotting and in situ hybridization.
The current areas of research in the laboratory are:
- Cellular and molecular mechanisms of long-term memory in the hippocampus.
- Possible similarities in memory storage between the immune system and the brain.
- Cellular and molecular characterization of the role of the ventral tegmentum in the
holeboard food search task.
For additional information go to
- Peņa de Ortiz, S., and Jamieson, G.A., Jr., 1996. Molecular cloning and brain
localization of HZF-2, a new member of the Rev-Erb family of orphan nuclear receptors.
- Peņa de Ortiz, S., and Jamieson, G.A., Jr., 1995. HZF-3, an immediate-early orphan
receptor homologous to NURR1/NOT: Induction upon membrane depolarization and seizures. In
- Peņa de Ortiz, S., Joe L. Martinez, Jr. And Jamieson, G.A., Jr., 1995. Inducible orphan
receptors: In search for a ligand and a function in the central nervous system: A review.
- Peņa de Ortiz, S., Cannon, M.M. and Jamieson, G.A., Jr., 1994. Expression of nuclear
hormone receptors within the rat hippocampus. Mol. Brain Res. 23:278-283.
- Cashman, J.R. and Peņa, S., 1989. Canrenone formation via general base-catalyzed
of 7-(methylthio) spironolactone S-oxide. Chem. Res. Toxicol. 2(2):109-113.
- Cashman, J.R. and Peņa, S., 1988. S-oxygenation of 7-thiomethylspironolactone by the
flavin containing monooxygenase. Drug Metab. Drug Interact. 6(3/4):337-348.
- Peņa de Ortiz, S., Derrick, E.B., and Martinez, J.L., Jr. The use of subtraction
cloning to identify genes associated with opioid receptor-dependent LTP in the
- Rivera, D.T., Peņa de Ortiz, S., Derrick, B.E., and Martinez, J.L., Jr. A recombinase
is member of a polycistronic cDNA associated with mossy fiber LTP. To be submitted to