Advancing age alters the contribution of calcium release from smooth endoplasmic reticulum stores in superior cervical ganglion cells.
In superior cervical ganglion (SCG) neurons calcium-induced calcium release (CICR), mediated by ryanodine receptors (RyRs), contributes to stimulation-evoked intracellular calcium ([Ca(2+)](i)) transients.


OBJECTIVE
The contribution of CICR to electrical field stimulation (EFS)-evoked [Ca(2+)](i) transients in SCG cells declines with senescence and may be partially recovered in the presence of caffeine. We measured EFS-evoked [Ca(2+)](i) transients in isolated fura-2-loaded SCG cells from Fischer-344 rats aged 6, 12, and 24 months with either the RyR antagonist ryanodine to block the contribution of CICR to [Ca(2+)](i) transients or caffeine to sensitize CICR to EFS. EFS-evoked [Ca(2+)](i) transients increased from 6 to 12 months and declined at 24 months and ryanodine decreased [Ca(2+)](i) transients in SCG cells from 6- and 12-month-old animals only. Caffeine significantly increased EFS-evoked [Ca(2+)](i) transients in all age groups. These data suggest that CICR declines with senescence and residual CICR function may be reclaimed in senescent cells with caffeine.
Behringer
Erik J
EJ
Department of Physiology and Pharmacology, Loma Linda University, CA 92354, USA.
Vanterpool
Conwin K
CK
Pearce
William J
WJ
Wilson
Sean M
SM
Buchholz
John N
JN
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D004558:Electric Stimulation; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D007424:Intracellular Fluid / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects / Q000378:metabolism; D017783:Superior Cervical Ganglion / Q000166:cytology / Q000378:metabolism*
D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D002110:Caffeine; D002118:Calcium