Different localizations and functions of L-type and N-type calcium channels during development of hippocampal neurons.
Using immunocytochemical assays and patch-clamp and calcium-imaging recordings, we demonstrate that L-type and N-type calcium channels have distinct patterns of expression and distribution and play different functional roles during hippocampal neuron differentiation. L-type channels, which support the depolarization-induced calcium influx in neurons from the very early developmental stages, are functionally restricted to the somatodendritic compartment throughout neuronal development and play a crucial role in supporting neurite outgrowth at early developmental stages. N-type channels, which start contributing at later neuronal differentiation stages (3-4 DIV), are also functionally expressed in the axons of immature neurons. At this developmental stage preceding synaptogenesis, N-type (but not L-type) channels are involved in controlling synaptic vesicle recycling. It is only at later developmental stages (10-12 DIV), when the neurons have established a clear axodendritic polarity and form synaptic contacts, that N-type channels are progressively excluded from the axon. Electrophysiological recordings of single neurons growing in microislands revealed that synaptic maturation coincides with a progressive increase in N-type channels in the somatodendritic region and a progressive decrease in the N-type channels supporting glutamate release from the presynaptic terminal. These results indicate that L-type and N-type calcium channels undergo dynamic, developmentally regulated rearrangements in regional distribution and function and also suggest that different mechanisms may be involved in the sorting and/or stabilization of these two types of channels in different plasma membrane domains during neuronal differentiation.
Pravettoni
E
E
Department of Medical Pharmacology, CNR Cellular and Molecular Pharmacology and "B. Ceccarelli" Centers, via Vanvitelli 32, Milan, 20129, Italy.
Bacci
A
A
Coco
S
S
Forbicini
P
P
Matteoli
M
M
Verderio
C
C
D000818:Animals; D001369:Axons / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D020864:Calcium Channels, N-Type / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002454:Cell Differentiation; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D007150:Immunohistochemistry; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D051381:Rats; D013572:Synaptic Vesicles / Q000378:metabolism; D020866:omega-Conotoxin GVIA / Q000494:pharmacology
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D020864:Calcium Channels, N-Type; D020866:omega-Conotoxin GVIA; D009543:Nifedipine