Measurements of intracellular calcium in sensory neurons of adult and old rats.
Cytosolic free calcium ([Ca2+]i) was measured using fluorescent digital imaging microscopy in rat dorsal root ganglion neurons isolated from animals of two age groups (adult: seven months; and old: 30 months). Neurons were enzymatically isolated and maintained in primary culture for 14 days. Cultured neurons were loaded with the fluorescent dye, Fura-2. The spatial distribution of resting [Ca2+]i was even in both adult and old rats, but the value of cytoplasmic free calcium in old neurons was significantly higher (207 +/- 37 nmol/l vs 96 +/- 23 nmol/l) in comparison with adult ones. Depolarization with 50 mmol/l K+ produced a rapid increase in [Ca2+]i in all neurons, but the values of depolarization-induced increase of [Ca2+]i in old neurons were significantly lower (423 +/- 54 nmol/l) compared with cells isolated from adult rats (1011 +/- 91 nmol/l). The time of the complete restoration of [Ca2+]i to the resting level was 10-times longer in old neurons. The caffeine-induced rise of intracellular calcium was somewhat higher in neurons from old animals, and its restoration to normal level was delayed. The findings indicate a substantial alteration of the mechanisms of regulation of intracellular calcium homeostasis with neuronal ageing.
Kirischuk
S
S
Bogomoletz Institute of Physiology, Kiev, Ukraine.
Pronchuk
N
N
Verkhratsky
A
A
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D005470:Fluorometry; D016257:Fura-2; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism; D006706:Homeostasis / Q000187:drug effects; D066298:In Vitro Techniques; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014700:Verapamil / Q000494:pharmacology
D014700:Verapamil; D002118:Calcium; D016257:Fura-2