Nuclear and cytoplasmic Ca2+ signals in developing rat dorsal root ganglion neurons studied in excised tissue.
Confocal microscopy and the Ca(2+)-sensitive fluorescent dye fluo-3 were used to study subcellular Ca2+ signals in embryonic, neonatal, and adult dorsal root ganglion (DRG) neurons in excised dorsal root ganglia. Optical images obtained from isolated whole embryonic and neonatal ganglia revealed a marked variability in the resting Ca2+ signals of different neurons as compared to signals in adult neurons which were uniformly faint. Many of the embryonic and neonatal neurons displayed nuclear Ca2+ signals at rest which were larger than those in the cytoplasm. Embryonic DRG neurons showed a significant increase in nuclear and cytoplasmic fluorescence in response to depolarization with elevated extracellular potassium or electrical stimulation. A single brief electrical stimulus was sufficient to elicit nuclear Ca2+ signals in a subset of the embryonic neurons. The depolarization-induced Ca2+ signals were blocked by removal of extracellular Ca2+, but not by treatment with 2,5-di (tert-butyl)-1,4 benzohydroquinone (DTBHQ), a compound which depletes intracellular Ca2+ stores. The intensity of the depolarization-induced Ca2+ signals declined significantly between the late embryonic (E18-E20) and early postnatal time periods (P0-P1). The nuclear and cytoplasmic Ca2+ signals of the embryonic DRG neurons in the excised tissue preparation occur at a time of intense target innervation, suggesting a role for Ca2+ signals in the development and maturation of rat DRG neurons.
Utzschneider
D A
DA
Department of Neurology, Yale University School of Medicine, New Haven, CT 06510.
Rand
M N
MN
Waxman
S G
SG
Kocsis
J D
JD
D000814:Aniline Compounds; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D004558:Electric Stimulation; D005314:Embryonic and Fetal Development / Q000502:physiology; D005456:Fluorescent Dyes; D005727:Ganglia, Spinal / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D007834:Lasers; D008853:Microscopy / Q000379:methods; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology*; D014966:Xanthenes
D000814:Aniline Compounds; D005456:Fluorescent Dyes; D014966:Xanthenes; C059715:Fluo-3