Da. Utzschneider et al., NUCLEAR AND CYTOPLASMIC CA2-ROOT GANGLION NEURONS STUDIED IN EXCISED TISSUE( SIGNALS IN DEVELOPING RAT DORSAL), Brain research, 635(1-2), 1994, pp. 231-237
Confocal microscopy and the Ca2+-sensitive fluorescent dye fluo-3 were
used to study subcellular Ca2+ signals in embryonic, neonatal, and ad
ult dorsal root ganglion (DRG) neurons in excised dorsal root ganglia.
Optical images obtained from isolated whole embryonic and neonatal ga
nglia revealed a marked variability in the resting Ca2+ signals of dif
ferent neurons as compared to signals in adult neurons which were unif
ormly faint. Many of the embryonic and neonatal neurons displayed nucl
ear Ca2+ signals at rest which were larger than those in the cytoplasm
. Embryonic DRG neurons showed a significant increase in nuclear and c
ytoplasmic fluorescence in response to depolarization with elevated ex
tracellular potassium or electrical stimulation. A single brief electr
ical stimulus was sufficient to elicit nuclear Ca2+ signals in a subse
t of the embryonic neurons. The depolarization-induced Ca2+ signals we
re blocked by removal of extracellular Ca2+, but not by treatment with
2,5-di(telt-butyl)-1,4 benzohydroquinone (DTBHQ), a compound which de
pletes 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 c
ytoplasmic Ca2+ signals of the embryonic DRG neurons in the excised ti
ssue preparation occur at a time of intense target innervation, sugges
ting a role for Ca2+ signals in the development and maturation of rat
DRG neurons.