Heterogeneous function of ryanodine receptors, but not IP3 receptors, in hamster cremaster muscle feed arteries and arterioles.
نویسندگان
چکیده
The roles played by ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP₃Rs) in vascular smooth muscle in the microcirculation remain unclear. Therefore, the function of both RyRs and IP₃Rs in Ca(²+) signals and myogenic tone in hamster cremaster muscle feed arteries and downstream arterioles were assessed using confocal imaging and pressure myography. Feed artery vascular smooth muscle displayed Ca(²+) sparks and Ca(²+) waves, which were inhibited by the RyR antagonists ryanodine (10 μM) or tetracaine (100 μM). Despite the inhibition of sparks and waves, ryanodine or tetracaine increased global intracellular Ca(²+) and constricted the arteries. The blockade of IP₃Rs with xestospongin D (5 μM) or 2-aminoethoxydiphenyl borate (100 μM) or the inhibition of phospholipase C using U-73122 (10 μM) also attenuated Ca(2+) waves without affecting Ca(²+) sparks. Importantly, the IP₃Rs and phospholipase C antagonists decreased global intracellular Ca(2+) and dilated the arteries. In contrast, cremaster arterioles displayed only Ca(²+) waves: Ca(²+) sparks were not observed, and neither ryanodine (10-50 μM) nor tetracaine (100 μM) affected either Ca(²+) signals or arteriolar tone despite the presence of functional RyRs as assessed by responses to the RyR agonist caffeine (10 mM). As in feed arteries, arteriolar Ca(²+) waves were attenuated by xestospongin D (5 μM), 2-aminoethoxydiphenyl borate (100 μM), and U-73122 (10 μM), accompanied by decreased global intracellular Ca(²+) and vasodilation. These findings highlight the contrasting roles played by RyRs and IP₃Rs in Ca(²+) signals and myogenic tone in feed arteries and demonstrate important differences in the function of RyRs between feed arteries and downstream arterioles.
منابع مشابه
Function and expression of ryanodine receptors and inositol 1,4,5-trisphosphate receptors in smooth muscle cells of murine feed arteries and arterioles.
We tested the hypothesis that vasomotor control is differentially regulated between feed arteries and downstream arterioles from the cremaster muscle of C57BL/6 mice. In isolated pressurized arteries, confocal Ca(2+) imaging of smooth muscle cells (SMCs) revealed Ca(2+) sparks and Ca(2+) waves. Ryanodine receptor (RyR) antagonists (ryanodine and tetracaine) inhibited both sparks and waves but i...
متن کاملPropagation of vasodilation in resistance vessels of the hamster: development and review of a working hypothesis.
In many tissues, a substantial fraction of total vascular resistance resides in the feed arteries that give rise to the microcirculation. We have explored the thesis that control of tissue blood flow is integrated over several levels of the vascular network, including feed arteries and microvessels. In response to muscular contraction, feed arteries (resting diameter 100-125 microns) of hamster...
متن کاملDifferential effects of diet-induced obesity on BKCa 1-subunit expression and function in rat skeletal muscle arterioles and small cerebral arteries
Howitt L, Sandow SL, Grayson TH, Ellis ZE, Morris MJ, Murphy TV. Differential effects of diet-induced obesity on BKCa 1-subunit expression and function in rat skeletal muscle arterioles and small cerebral arteries. Am J Physiol Heart Circ Physiol 301: H29–H40, 2011. First published May 2, 2011; doi:10.1152/ajpheart.00134.2011.— Mechanisms underlying obesity-related vascular dysfunction are uncl...
متن کاملDifferential inhibition of functional dilation of small arterioles by indomethacin and glibenclamide.
Indomethacin or glibenclamide treatments attenuate functional dilation of larger-diameter "feed" arterioles paired with venules in hamster cremaster muscle. We tested the hypothesis that release of cyclooxygenase products from venules is important for functional dilation of third- and fourth-order arterioles. We also tested whether ATP-sensitive potassium channels are important during functiona...
متن کاملDifferential effects of diet-induced obesity on BKCa {beta}1-subunit expression and function in rat skeletal muscle arterioles and small cerebral arteries.
Mechanisms underlying obesity-related vascular dysfunction are unclear. This study examined the effect of diet-induced obesity on expression and function of large conductance Ca(2+)-activated potassium channel (BK(Ca)) in rat pressurized small resistance vessels with myogenic tone. Male Sprague-Dawley rats fed a cafeteria-style high fat diet (HFD; ∼30% energy from fat) for 16-20 wk were ∼30% he...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- American journal of physiology. Heart and circulatory physiology
دوره 300 5 شماره
صفحات -
تاریخ انتشار 2011