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Effects of beta-catenin on dendritic morphology and simulated firing patterns in cultured hippocampal neurons

Biol Bull. 2006 Aug;211(1):31-43. doi: 10.2307/4134575.

Abstract

Beta-catenin is an intracellular signaling molecule that has been shown to be important in activity-dependent dendritic morphogenesis. Here, we investigate the detailed morphological changes elicited in dendritic arbors of cultured hippocampal neurons by overexpression of beta-catenin, and we simulate the electrophysiological consequences of these changes. Compared to control neurons, cells overexpressing beta-catenin have dendritic arbors with significantly greater surface area and more branches, as well as different topological characteristics. To investigate possible effects of beta-catenin expression on the electrophysiological properties of neurons, we converted confocal images of neurons expressing beta-catenin into computational simulator formats using parameters that evenly distributed voltage-dependent channels across the cells' membranes. In simulated current clamp experiments, somata were injected with a normalized current such that the observed electrophysiological differences in the neurons would be due only to morphological differences. We found that the morphology of beta-catenin-expressing neurons contributes to significantly smaller action potential amplitude and greater sensitivity than seen in control neurons. As a consequence, beta-catenin-expressing neurons tended to exhibit higher spike rates and needed less excitation to induce firing. These findings show that beta-catenin, by modifying dendritic arborization, could have profound influences on the electrophysiological behavior of neurons.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Computer Simulation
  • Gene Expression Regulation
  • Hippocampus / cytology*
  • Models, Biological
  • Nerve Net / drug effects
  • Neurons / cytology*
  • Neurons / metabolism*
  • beta Catenin / metabolism*

Substances

  • beta Catenin