title: Developmental profile of localized spontaneous Ca(2+) release events in the dendrites of rat hippocampal pyramidal neurons.
abstract: Recent experiments demonstrate that localized spontaneous Ca(2+) release events can be detected in the dendrites of pyramidal cells in the hippocampus and other neurons (J. Neurosci. 29 (2009) 7833-7845). These events have some properties that resemble ryanodine receptor mediated "sparks" in myocytes, and some that resemble IP(3) receptor mediated "puffs" in oocytes. They can be detected in the dendrites of rats of all tested ages between P3 and P80 (with sparser sampling in older rats), suggesting that they serve a general signaling function and are not just important in development. However, in younger rats the amplitudes of the events are larger than the amplitudes in older animals and almost as large as the amplitudes of Ca(2+) signals from backpropagating action potentials (bAPs). The rise time of the event signal is fast at all ages and is comparable to the rise time of the bAP fluorescence signal at the same dendritic location. The decay time is slower in younger animals, primarily because of weaker Ca(2+) extrusion mechanisms at that age. Diffusion away from a brief localized source is the major determinant of decay at all ages. A simple computational model closely simulates these events with extrusion rate the only age dependent variable.
authors.affiliation: Department of Physiology, New York Medical College, Valhalla, NY 10595, United States.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Miyazaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Manita
authors.forename: William N
authors.initials: WN
authors.lastname: Ross
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D003712:Dendrites / Q000378:metabolism*; D066298:In Vitro Techniques; D008954:Models, Biological; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D002118:Calcium