email: schandler@physci.ucla.edu
phone: (310) 206-6636
office: 2859 slichter hall
research interests: Neuronal Mechanisms Controlling Jaw Movement
Research Interests
My interests are in the area of neuronal mechanisms controlling rhythmical jaw movements that occur during such behaviors as feeding, drinking and swallowing. These are all behaviors essential for normal, meaningful human existence. Using rat and guinea pig models, I am interested in elucidating the location of, and cellular connectivity of the central circuits, as well as the neurochemical and physiological mechanisms underlying the control of excitability of the neurons within these circuits which are responsible for the production of jaw movements. Our approach is to use electrophysiological, pharmacological and anatomical techniques in both whole animal and in vitro brain slice preparations. Utilizing these techniques we have located the critical regions and premotoneurons responsible for the rhythmogenesis of mastication to a narrow area within the ponto-medullary brainstem. Investigations into the roles of excitatory amino acid receptor subtypes in production of jaw movements showed that both NMDA and nonNMDA receptors are important in the initiation and control of rhythmical jaw movements. The ionic conductances available to masticatory interneurons and motoneurons have been characterized as well as the modulation of these conductances by various neuromessengers. Additionally, we recently found a group of interneurons around the trigeminal motor nucleus which have intrinsic burst generation properties. These neurons could serve as the fundemental unit for rhythmogenesis during jaw movements. Progress in these areas will allow us to ultimately understand organizing principles utilized by the mammalian CNS with respect to motor production and to determine potential therapeutic interventions for the correction of abnormal jaw movements which occurs as a result of injury or disease.
Selected Publications
Enomoto, A., Han, J.M., Hsiao, C.F. and Chandler, S.H.. 2007. Sodium currents in mesencephalic trigeminal neurons from Nav1.6 null mice, J Neurophysiol 98 710-719 .
Hsiao, C.F., Gougar, K., Asai, J. and Chandler, S.H. 2007. Intrinsic membrane properties and morphological characteristics of interneurons in the rat supratrigeminal region J.Neurosci. Res 85 3673-3686 .
Tanaka, S. and Chandler, S.H.. 2006. Serotonergic modulation of persistent sodium currents and membrane excitability via cyclic AMP-protein kinase A cascade in mesencephalic V neurons J Neurosci Res 83 1362-1372 .
Enomoto, A., Han, J.M., Hsiao, C.F., Wu, N. and Chandler, S.H.. 2006. Participation of sodium currents in burst generation and control of membrane excitability in mesencephalic trigeminal neurons J Neurosci 26 3412-3422 .
Wu N., Enomoto, A., Tanaka, S., Hsiao, C.F., Nykamp, D.Q., Izhikevich, E. and Chandler, S.H.. 2005. Persistent sodium currents in mesencephalic V neurons participate in burst generation and control of membrane excitability J. Neurophysiol 93 2710-2822 .
Hsiao, C.F., Wu, N. and Chandler, S.H.. 2005. Voltage-Dependent calcium currents in trigeminal motoneurons of early postnatal rats: Modulation by 5-HT receptors J. Neurophysiol 94 2063-2072 .
Starling, A.J., Andre, V.M., Cepeda, C, de Lima, M., Chandler, S.H. and Levine, M.S.. 2005. Alterations in N-methyl-D-aspartate receptor sensitivity and magnesium blockade occur early in development in the R6/2 mouse model of Huntington's disease J. Neurosci. Res 82 377-386 .
Ariano, M.A., Cepeda, C., Calvert, C.R., Flores-Hernandez, J., Hernandez-Echeagaray, E., Klapstein, G.J., Chandler, S.H., Aronin, N., DiFiglia, M. and Levine, M.S.. 2004. Striatal potassium channel dysfunction in Huntington's disease transgenic mice J. Neurophysiol 93 2565-2574 .
Tanaka, S., Wu, N., Hsaio, C-F., Turman, J. and Chandler, S.H.. 2003. Developement of Inward rectification and Control of Membrane Excitability in Mesencephalic V Neurons, J. Neurophysiol 89 1288-1298 .
Hsiao, C.F., Wu, N., Levine, M.S. and Chandler, S.H.. 2002. The development of serotonergic modulation of NMDA bursting in rat trigeminal motoneurons J. Neurophysiol 87 1318-1328 .