Local increases in intracellular calcium elicit local filopodial responses in Helisoma neuronal growth cones.
Highly localized changes in intracellular Ca2+ concentration ([Ca2+]i) can be evoked in neuronal growth cones; these are followed by local changes in filopodia. Focally applied electric fields evoked spatially restricted, high magnitude increases in growth cone [Ca2+]i. The earliest and greatest increases were localized to small regions within a growth cone. Such fields also produced characteristic changes in the disposition of filopodia: both filopodial length and number were significantly increased on the cathode side of growth cones. The requirement for extracellular Ca2+ and the strong correlation between the evoked rise in [Ca2+]i and the changes in filopodia (r = 0.98) indicate that cathode stimulation results in local Ca2+ influx, leading to locally increased [Ca2+]i and local changes in filopodial behavior.
Davenport
R W
RW
Department of Anatomy and Neurobiology, Colorado State University, Fort Collins 80523.
Kater
S B
SB
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004558:Electric Stimulation; D007425:Intracellular Membranes / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D009994:Osmolar Concentration; D012908:Snails; D013997:Time Factors
D002118:Calcium