Premium
Heterogeneous roles for FK506 binding proteins in the regulation of calcium signaling and myogenic tone in hamster cremaster feed arteries and arterioles
Author(s) -
Westcott Erika Boerman,
Jackson William F
Publication year - 2011
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.25.1_supplement.817.4
The FK506 Binding Proteins (FKBP) modulate the function of ryanodine receptors (RyR), but their role in the microcirculation has not been studied. In contrast to their function in upstream arteries, RyR are silent in hamster cremaster arterioles (HCA), suggesting no role for FKBP in those vessels. We used rapamycin (RAPA) and FK506 to test the hypothesis that FKBP‐RyR interaction is important to the regulation of Ca 2+ signaling and myogenic tone in hamster cremaster feed arteries (HFA), but not in HCA. In cannulated vessels, pressurized to 80 cm H 2 O and loaded with the Ca 2+ indicator, Fluo 4, RAPA or FK506 (10 μM) each dilated HFA (18 ± 2% and 14 ± 3%), and decreased global Ca 2+ (39 ± 10% and 32 ± 11%). HFA displayed Ca 2+ sparks with amplitude (AMP) of 1.34 ± 0.01 F/Fo and frequency (FQ) of 0.20 ± 0.01 Hz, which were abolished by both RAPA and FK506. Ca 2+ waves also were attenuated: Occurrence (OC), AMP and FQ were decreased from 62 ± 12%, 1.80 ± 0.27, and 0.36 ± 0.15 Hz at rest, to 3 ± 8%; 1.27 ± 0.06 F/Fo and 0.09 ± 0.03 Hz using RAPA, or to 4 ± 8%, 1.26 ± 0.04 F/Fo and 0.06 ± 0.02 Hz with FK506 (p < 0.05). Ca 2+ sparks were not observed in HCA, and neither RAPA nor FK506 altered global Ca 2+ , diameter or OC, AMP or FQ of Ca 2+ waves in HCA (p > 0.05). These data support the hypothesis that there are differences in RyR function and regulation between HFA and HCA. Supported by RO1 HL 32469, PO1 HL070687 and AHA Fellowship 0815778G.