Raising the speed limit--fast Ca(2+) handling in dendritic spines.
Ca2+ influx into dendritic spines is involved in the induction of both long-term potentiation (LTP) and long-term depression (LTD) by activating distinct biochemical cascades, depending on the stimulation protocol. Such conditional activation can be explained by the finding that removal of Ca2+ from spines is extremely rapid (approximately 15 ms) and promoted by a low endogenous buffering capacity. As a consequence, the time course of influx and binding kinetics are important determinants of how much Ca2+ binds to a particular enzyme. In addition structural factors, such as shape and dendritic location, could contribute to fine-tuning of spine Ca2+ handling and synaptic modification.
Abteilung Zellphysiologie, Max-Planck-Institute für medizinische Forschung, Jahnstr. 29, 69120 Heidelberg, Germany. fritjof@mpimf-heidelberg.mpg.de
Fritjof
F
Helmchen
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003712:Dendrites / Q000502:physiology*; D006801:Humans; D009473:Neuronal Plasticity / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology
D016194:Receptors, N-Methyl-D-Aspartate; D002118:Calcium