Effects of Temperature on Calcium Transients and Ca2+-Dependent Afterhyperpolarizations in Neocortical Pyramidal Neurons
Open Access
- 1 April 2005
- journal article
- research article
- Published by American Physiological Society in Journal of Neurophysiology
- Vol. 93 (4), 2012-2020
- https://doi.org/10.1152/jn.01017.2004
Abstract
In neocortical pyramidal neurons, the medium (mAHP) and slow AHP (sAHP) have different relationships with intracellular [Ca2+]. To further explore these differences, we varied bath temperature and compared passive and active membrane properties and Ca2+transients in response to a single action potential (AP) or trains of APs. We tested whether Ca2+-dependent events are more temperature sensitive than voltage-dependent ones, the slow rise time of the sAHP is limited by diffusion, and temperature sensitivity differs between the mAHP and sAHP. The onset and decay kinetics of the sAHP were very temperature sensitive (more so than diffusion). We found that the decay time course of Ca2+transients was also very temperature sensitive. In contrast, the mAHP (amplitude, time to peak, and exponential decay) and sAHP peak amplitude were moderately sensitive to temperature. The amplitudes of intracellular Ca2+transients evoked either by a single spike or a train of spikes showed modest temperature sensitivities. Pyramidal neuron input resistance was increased by cooling. With the exception of threshold, which remained unchanged between 22 and 35°C, action potential parameters (amplitude, half-width, maximum rates of rise and fall) were modestly affected by temperature. Collectively, these data suggest that temperature sensitivity was higher for the Ca2+-dependent sAHP than for voltage-dependent AP parameters or for the mAHP, diffusion of Ca2+over distance cannot explain the slow rise of the sAHP in these cells, and the kinetics of the sAHP and mAHP are affected differently by temperature.Keywords
This publication has 68 references indexed in Scilit:
- Small Conductance Ca2+-Activated K+ Channel Knock-Out Mice Reveal the Identity of Calcium-Dependent Afterhyperpolarization CurrentsJournal of Neuroscience, 2004
- SKCaChannels Mediate the Medium But Not the Slow Calcium-Activated Afterhyperpolarization in Cortical NeuronsJournal of Neuroscience, 2004
- Small conductance Ca2+‐activated K+ channels and calmodulinThe Journal of Physiology, 2004
- Relationships Between Intracellular Calcium and Afterhyperpolarizations in Neocortical Pyramidal NeuronsJournal of Neurophysiology, 2004
- Detailed passive cable models of layer 2/3 pyramidal cells in rat visual cortex at different temperaturesThe Journal of Physiology, 2002
- Back‐propagating action potentials mediate calcium signalling in dendrites of bitufted interneurons in layer 2/3 of rat somatosensory cortexThe Journal of Physiology, 2001
- The reliability of excitatory synaptic transmission in slices of rat visual cortex in vitro is temperature dependentThe Journal of Physiology, 1998
- Nimodipine decreases calcium action potentials in rabbit hippocampal CA1 neurons in an age‐dependent and concentration‐dependent mannerHippocampus, 1994
- The ontogeny of repetitive firing and its modulation by norepinephrine in rat neocortical neuronsDevelopmental Brain Research, 1993
- The effect of pH on rate constants, ion selectivity and thermodynamic properties of fluorescent calcium and magnesium indicatorsBiochemical and Biophysical Research Communications, 1991