Voltage-activated intracellular calcium transients in thalamic relay cells and interneurons.
The dynamics of intracellular calcium concentration ([Ca2+]i) following activation of low voltage-activated (LVA) and high voltage-activated (HVA) Ca2+ currents were studied in identified relay neurons and interneurons of the rat dorsal lateral geniculate nucleus (LGNd) in situ using Ca2+ imaging and patch-clamp techniques. In relay neurons, [Ca2+]i transients associated with the LVA Ca2+ current showed a fairly homogeneous somatodendritic distribution, whereas HVA transients significantly decreased to 65% of the somatic value at 60 microns dendritic distance. In interneurons, LVA transients significantly increased to 239% of the somatic value at 60 microns dendritic distance, whereas HVA transients were not significantly different in the soma and dendrites. These results indicate differences in [Ca2+]i dynamics, which may reflect a heterogeneous distribution of Ca2+ channels contributing to subcellular compartmentation in the two types of thalamic neurons.
Munsch
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Institut für Physiologie, Medizinische Fakultät, Otto-von-Guericke Universität, Magdeburg, Germany.
Budde
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Pape
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D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D003712:Dendrites / Q000502:physiology; D005071:Evoked Potentials; D005829:Geniculate Bodies / Q000502:physiology*; D066298:In Vitro Techniques; D007395:Interneurons / Q000502:physiology*; D008564:Membrane Potentials; D018715:Microscopy, Video; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar
D015220:Calcium Channels; D002118:Calcium