1. Role of different intracellular membrane pools in the regulation of apical membrane permeability in tight epithelia.
The goal of these studies is to determine whether different hormones activate apical membrane permeability through the same mechanism. Our initial studies show that the major regulatory pathways involve insertion of preexisting channels from an intracellular pool or pools. We are now investigating whether or not the channels inserted under the influence of different hormones originate in the same or separate membrane pools. The experiments involve continuous measurements of membrane conductance and capacitance.
2. Role of extrastriatal pathways in the regulation of motor behavior by the basal ganglia.
Since it was recognized that abnormalities of dopaminergic transmission cause Parkinson's disease and also may be responsible for a variety of psychiatric disorders, a lot of effort has been invested in studying the role of dopaminergic control of the basal ganglia The majority of the studies have been concerned with defining the role of the striatum. We are now studying the role of the dopaminergic innervation of the external globus pallidus. By combining measurements of single cell electrical activity, transmitter release and motor behavior we have established that this structure is a major site of motor control mediated through dopaminergic D2 receptors and that deficits in this process can cause major impairments in motor behavior.
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Gonzalez, B., Paz, F., Florán, L., Aceves, J., Erlij, D., and Florán, B. (2006). Adenosine A2A receptor stimulation decrease GAT-1-mediated GABA uptake in the globus pallidus of the rat. Neuropharmacol. 51, 154-159.
Anaya-Martinez, V., Martinez-Marcos, A., Martinez-Fong, D., Aceves, J., and Erlij, D.(2006). Substantia nigra compacta neurons that innervate the reticular thalamic nucleus in the rat also project to striatum or globus pallidus: implications for abnormal motor behavior. Neuroscience 143, 477-486.
Silva, I., Cortes, H., Escartin, E., Rangel, C., Florán, L., Erlij, D., Aceves, J., and Florán, B. (2006). L-DOPA inhibits depolarization-induced [3H]GABA release in the dopamine-denervated globus pallidus of the rat: the effect is dopamine-independent and mediated by D2-like receptors. J. Neural Transmission 113, 1847-1853.
Ibanez-Sandoval, O., Hernandez, A., Florán, B., Galárraga, E., Tapia, D., Valdiosera, R., Erlij, D., Aceves, J., and Bargas, J. (2006). Control of subthalamic innervation of substantia nigra pars reticulata by D1 and D2 dopamine receptors. J. Neurophysiol. 95, 1800-1811.