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IMPACT OF ADVANCING AGE ON CAFFEINE MEDIATED SENSITIZATION OF CALCIUM RELEASE IN SUPERIOR CERVICAL GANGLION CELLS.
Author(s) -
Behringer Erik J,
Vanterpool Conwin K,
Pearce William J,
Buchholz John N
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1126.7
Subject(s) - caffeine , ryanodine receptor , stimulation , endocrinology , calcium , medicine , superior cervical ganglion , chemistry , calcium in biology
In vascular sympathetic neurons calcium‐induced calcium release (CICR) is mediated by ryanodine receptors (RyR) and contributes to the magnitude of stimulation‐evoked intracellular calcium ([Ca 2+ ]i) transients. Furthermore, this process can be sensitized with RyR agonists such as caffeine. In this study we assessed the contribution of CICR to the magnitude of electric field stimulation (EFS)‐evoked [Ca 2+ ]i transients. We measured EFS‐evoked changes in [Ca 2+ ]i in isolated fura‐2 loaded superior cervical ganglion (SCG) cells, from F‐344 rats aged 6, 12, and 24 months. EFS was delivered over a range of 3 to 24 pulses (3Hz) in the absence and presence of 5mM caffeine. Maximal EFS‐evoked increases in [Ca 2+ ]i significantly increased from 6‐12 months and then declined at 24 months, suggesting that CICR as a component of the EFS‐evoked [Ca 2+ ]i transient declines with age. However, most interestingly, caffeine significantly increased EFS‐evoked [Ca 2+ ]i transients over the entire stimulation range (3–24 pulses) in all age groups. In addition, caffeine decreased the number of pulses to achieve ½ maximal EFS‐evoked [Ca 2+ ]i in all age groups. Taken together, the data suggest that with advancing age although the contribution of CICR to EFS‐evoked [Ca 2+ ]i transients may decline with age, some of this function can be reclaimed in the presence of RyR agonists such as caffeine. Supported in part by NIH HED P01 #31226