Extracellular calcium depletion in synaptic transmission.
Regulation of Ca2+ homeostasis in the extracellular space plays an important role in neuronal function. Several modeling studies and recent measurements have demonstrated that modest action potential or synaptic activity can result in a significant reduction in extracellular calcium ([Ca]o(2+)). Changes in [Ca]o(2+) can regulate intracellular signaling enzymes, such as Ca2+/calmodulin-dependent protein kinase II, and influence neuronal function at synaptic and nonsynaptic sites. The change in [Ca]o(2+) can affect several types of ion channels and neurotransmitter receptors and activate a Ca(2+)-sensitive receptor in neuronal membranes. Depletion of [Ca]o(2+) may function as an activity-dependent extracellular messenger that regulates nervous system function during development, learning, and disease.
National Institutes of Health, National Institute for Child and Human Development, Section on Nervous System Development and Plasticity, Bethesda, MD 20892, USA.
Jonathan E
JE
Cohen
R Douglas
RD
Fields
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D045604:Extracellular Fluid / Q000378:metabolism*; D006801:Humans; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology*
D043562:Receptors, G-Protein-Coupled; D002118:Calcium