Mechanical stimuli induce intracellular calcium response in a subpopulation of cultured rat sensory neurons.
Cultured dorsal root ganglion neurons from newborn rats were mechanically deformed with a fine-tipped glass capillary, and the change in the intracellular Ca2+ concentration ([Ca2+]i) was recorded by Fura-2-based microfluorimetry. The deformation evoked elevation in [Ca2+]i from 18.7 +/- 5.4 nM (mean +/- S.E.M., n = 35) to 137.1 +/- 15.2 nM in some subpopulations of cells, especially those larger than 20 microm in diameter. The largest mechanosensitive cell group was that of cells 20-25 microm in diameter; 56% of the mechanosensitive cells were of this cell size. All of the cells larger than 25 microm in diameter displayed the Ca2+ increase when prodded. The depletion of extracellular Ca2+ diminished the Ca2+ elevation. Verapamil and nickel, blockers of voltage-dependent Ca2+ channels, did not influence the Ca2+ response, whereas gadolinium, a relatively selective blocker of mechanosensitive channels, diminished the response. Na+-free conditions did not influence the response. We concluded that the mechanical stimulation induced a Ca2+ influx in large dorsal root ganglion neurons through mechanosensitive Ca2+-permeable channels.
Gotoh
H
H
Department of Bioengineering, Faculty of Engineering, Soka University, Hachioji, Tokyo, Japan.
Takahashi
A
A
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D020864:Calcium Channels, N-Type; D020013:Calcium Signaling / Q000502:physiology*; D002478:Cells, Cultured; D003592:Cytophotometry; D005682:Gadolinium / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000166:cytology / Q000502:physiology; D008465:Mechanoreceptors / Q000502:physiology*; D009475:Neurons, Afferent / Q000378:metabolism* / Q000502:physiology* / Q000648:ultrastructure; D009532:Nickel / Q000494:pharmacology; D010812:Physical Stimulation; D051381:Rats; D012964:Sodium / Q000502:physiology; D014700:Verapamil / Q000494:pharmacology
D002118:Calcium; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D020864:Calcium Channels, N-Type; D005682:Gadolinium; D009532:Nickel; D012964:Sodium; D014700:Verapamil