| First Author | Harraz OF | Year | 2015 |
| Journal | Arterioscler Thromb Vasc Biol | Volume | 35 |
| Issue | 8 | Pages | 1843-51 |
| PubMed ID | 26069238 | Mgi Jnum | J:241914 |
| Mgi Id | MGI:5903846 | Doi | 10.1161/ATVBAHA.115.305736 |
| Citation | Harraz OF, et al. (2015) Genetic ablation of CaV3.2 channels enhances the arterial myogenic response by modulating the RyR-BKCa axis. Arterioscler Thromb Vasc Biol 35(8):1843-51 |
| abstractText | OBJECTIVE: In resistance arteries, there is an emerging view that smooth muscle CaV3.2 channels restrain arterial constriction through a feedback response involving the large-conductance Ca(2+)-activated K(+) channel (BKCa). Here, we used wild-type and CaV3.2 knockout (CaV3.2(-/-)) mice to definitively test whether CaV3.2 moderates myogenic tone in mesenteric arteries via the CaV3.2-ryanodine receptor-BKCa axis and whether this regulatory mechanism influences blood pressure regulation. APPROACH AND RESULTS: Using pressurized vessel myography, CaV3.2(-/-) mesenteric arteries displayed enhanced myogenic constriction to pressure but similar K(+)-induced vasoconstriction compared with wild-type C57BL/6 arteries. Electrophysiological and myography experiments subsequently confirmed the inability of micromolar Ni(2+), a CaV3.2 blocker, to either constrict arteries or suppress T-type currents in CaV3.2(-/-) smooth muscle cells. The frequency of BKCa-induced spontaneous transient outward K(+) currents dropped in wild-type but not in knockout arterial smooth muscle cells upon the pharmacological suppression of CaV3.2 channel. Line scan analysis performed on en face arteries loaded with Fluo-4 revealed the presence of Ca(2+) sparks in all arteries, with the subsequent application of Ni(2+) only affecting wild-type arteries. Although CaV3.2 channel moderated myogenic constriction of resistance arteries, the blood pressure measurements of CaV3.2(-/-) and wild-type animals were similar. CONCLUSIONS: Overall, our findings establish a negative feedback mechanism of the myogenic response in which CaV3.2 channel modulates downstream ryanodine receptor-BKCa to hyperpolarize and relax arteries. |
