C. Fernando Valenzuela, M.D., Ph.D.

 Associate Professor

 Department of Neurosciences

Educational History
Ph.D. (1993) University of California , Riverside , CA. Major: Biomedical Sciences.
M.D. with Honors (1987) Colombian School of Medicine (Universidad El Bosque) Bogota , Colombia .

Employment History
 Director, MD/PhD Program (2005-Present), University of New Mexico School of Medicine , Albuquerque , NM
Associate Professor (2005-Present), Department of Neurosciences, University of New Mexico School of Medicine , Albuquerque , NM .
Assistant Professor (1998-2004), Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM.
Instructor (1996-1998), Department of Pharmacology, University of Colorado HSC, Denver, CO.
Postdoctoral Fellow (1993-1996), Department of Pharmacology, University of Colorado HSC, Denver, CO.

Research Interests
An important area of research interest the laboratory is the mechanism of action of neurosteroids and the role of these agents in fetal alcohol syndrome. We have recently demonstrated a novel presynaptic effect of neurosteroids that implicates these agents as important regulators of neuronal development. Importantly, fetal alcohol exposure produces a dramatic elevation of pregnenolone sulfate levels and premature activation of silent synapses, which could explain some of the synapse maturation abnormalities that characterize fetal alcohol syndrome.

Another line of research concerns the effects of ethanol on oscillatory activity in the immature brain. We have been focusing on the developing hippocampus, which is important for learning and memory processes and is particularly sensitive to the neuroteratogenic effects of ethanol. In this brain region, there is a primitive pattern of network-driven electrical activity known as the giant depolarizing potentials (GDPs). In immature neurons, GABA A receptors are excitatory due to an increase in the intracellular concentration of Cl -. The excitatory actions of GABA generate these GDPs, which are associated with large oscillations in intracellular calcium. These oscillations contribute to activity dependent modulation of neuronal growth and synaptogenesis. We found that ethanol alters the normal pattern of this primitive oscillatory network activity and are currently characterizing the mechanism of this effect using hippocampal slices.

We are also studying the effects of alcohol on the function of neuronal circuits in the mature brain. More recently, we have extended these studies to cerebellar circuits. Neurons of the cerebellar cortex play a central role in the control of motor functions. These neurons form a basic circuit unit and Purkinje neurons are the main output of this circuit. Our data suggest that ethanol depresses synaptic transmission in the mature cerebellar cortex by presynaptically modulating neurotransmitter release at major synapses within the basic circuit unit. We are currently using the cerebellar slice preparation and patch-clamp electrophysiological techniques to further characterize this action of ethanol.

Selected Publications

 

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