Calcium currents in rat entorhinal cortex layer II stellate and layer III pyramidal neurons in acute brain slice.
The entorhinal cortex (EC) is an essential relay station in neocortical - hippocampal information transfer and memory functions. Layer II stellate and layer III pyramidal neurons show specific damage in Alzheimer's disease and epilepsy, respectively. Using whole cell patch clamp recording in rat brain slices we here demonstrate that high voltage activated Ca(2+)-currents (I(Ca)(2+)) are about 1.6-fold bigger in stellate cells than in pyramidal neurons while current density is equal in both cell types. In stellate cells I(Ca)(2+) shows stronger inactivation with depolarization, block of I(Ca)(2+) by Ni(2+) (300 and 600 microM) is more effective, and this block decreases more for currents evoked from a less negative holding potential than in layer III pyramidal neurons. These data indicate distinct molecular composition of Ca(2+)-channels and can partially explain stronger increases of [Ca(2+)](i) during 10 Hz firing activity in EC pyramidal versus stellate neurons.
AG Molekulare Zellphysiologie, Neurowissenschaftliches Forschungszentrum der Charité, Humboldt Universität zu Berlin, Schumannstrasse 20/21, D-10117, Berlin, Germany.
Violeta
V
Visan
Uwe
U
Heinemann
Andriy
A
Volynets
Wolfgang
W
Müller
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D018728:Entorhinal Cortex / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009532:Nickel / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013233:Stellate Ganglion / Q000502:physiology
D015220:Calcium Channels; D009532:Nickel