Effects of CaMKII-Mediated Phosphorylation of Ryanodine Receptor Type 2 on Islet Calcium Handling, Insulin Secretion, and Glucose Tolerance (original) (raw)
Figure 2
RyR2-mediated Ca2+ leak and basal hyperinsulinemia in S2814D mice.
(A) Representative cytoplasmic Ca2+ level ([Ca2+]cyt) tracings from islets following perfusion with 1 mM tetracaine (TTc). (B) Quantification of decrease in [Ca2+]cyt (represented in arbitary units (A.U.)) (greater Ca2+ leak) in S2814D islets compared to WT islets in response to 1 mM TTc. n>25 islets from 3 mice per group. (C) Average blood glucose levels in WT (N = 4) and S2814D (N = 14) mice after 6 h fasting. (D) Average serum insulin levels in WT (N = 4) and S2814D (N = 9) mice after 6 h fasting. Note higher baseline insulin levels in S2814D mice. (E) Representative immunohistochemical images of frozen pancreas sections from WT and S2814D mice. Islets were stained with glucagon (green) and insulin (red). Scale bar, 100 µm. (F) Quantification of percentage area of pancreatic tissue occupied by total islets or glucagon- or insulin-positive islet fractions in WT and S2814D mice. Number of mice (pancreata) and total number of islets studied indicated below the bars. Data are represented as average ± SEM. *P<0.05 vs. WT.