Calbindin D-28k is a dendritic marker in MNTB principal cells

Abstract

<p>The Medial Nucleus of the Trapezoid Body (MNTB) has received considerable attention in the discipline of synaptic physiology. For decades the direct examination of mammalian synapses in the CNS had been precluded by the small size and widespread distribution of synaptic terminals. However, the round morphology of the MNTB principal cell and the large size of its primary synaptic input, the glutamatergic calyx of Held, has recently allowed researchers to obtain simultaneous pre-and postsynaptic recordings without the electronic complications of dendritic filtering. However, the precise role of principal cell dendrites has yet to be defined and, the presence of significant functional dendritic inputs has become a contentious issue. Dendrites comprise up to 25% of the principal cell surface area, adding considerable capacitance to the neuron and creating tremendous potential to affect postsynaptic firing capabilities. While recent physiological data indicating active dendritic Na+ and K+ conductances may contribute to the faithful propagation of high frequency synaptic input suggests that principal cell dendrites not be so readily ignored, a reliable and effective immunohistochemical marker for them has yet to be identified and critical data regarding dendritic channel distribution and synaptic contacts yet to be obtained. This poster concerns preliminary observations using a method for direct immunohistochemical observations of MNTB principal cell dendrites. The objectives are to: 1) determine the expression of CB-D28k in the MNTB of normal hearing and congenitally deaf mice, 2) identify principal cell dendrites labeled by antibodies directed against CB-D28k, and 3) identify putative synaptic contacts and voltage gated potassium channels on principal cell dendrites.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 16, 2010</p>