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Differences in expression and function of ryanodine receptors between arteries and arterioles in the mouse
Author(s) -
Lange Erica,
Boerman Erika M.,
Segal Steven S.,
Jackson William F.
Publication year - 2010
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.24.1_supplement.777.5
Subject(s) - ryanodine receptor , endoplasmic reticulum , ryanodine receptor 2 , ryr1 , medicine , receptor , endocrinology , chemistry , vascular smooth muscle , biology , smooth muscle , microbiology and biotechnology , biochemistry
Ryanodine receptors (RyR) in smooth muscle cells (SMC) underlie Ca 2+ sparks and Ca 2+ ‐induced‐Ca 2+ release, contributing to the regulation of myogenic tone in arteries. In contrast, RyR are silent and are not involved in Ca 2+ signals in SMC or myogenic tone in hamster arterioles. The purpose of the present study was to investigate the role of RyR in vessels of male C57BL/6 mice. We tested the hypothesis that differences in RyR isoform expression contribute to differences in RyR function in iliac feed arteries (FA) vs. cremaster arterioles (CA). In cannulated pressurized (80 cm H 2 O) vessels (34 – 37 °C), ryanodine (10 μM) constricted FA (from 53 ± 4 to 40 ± 3 μm; n = 5, p < 0.05) but not CA (24 ± 2 μm vs. 22 ± 2 μm; n = 5, p > 0.05). Transcript levels for RyR2 in freshly isolated SMC assessed by q‐RT‐PCR were 2.1 ± 0.3 ‐fold higher in FA vs. CA (n = 7, p < 0.05), while those for RyR3 were 0.6 ± 0.1 in FA vs. CA (n = 6, p < 0.05). RyR1 transcripts were not detected in SMC from FA or CA. Immunofluorescence with an anti‐RyR1/2 antibody showed clustered labeling in FA SMC (n = 6 SMC) suggestive of RyR2 expression in endoplasmic reticulum. In contrast, more uniform cytoplasmic staining in CA SMC (n = 13 SMC) suggested non‐organelle‐specific staining. These data support our hypothesis and indicate fundamental differences in SMC RyR expression and function between arteries and arterioles across rodent species. Supported by NIH HL086483 & AHA Fellowship 0815778G.