
Objective— In resistance arteries, there is an emerging view that smooth muscle Ca V 3.2 channels restrain arterial constriction through a feedback response involving the large-conductance Ca 2+ -activated K + channel (BK Ca ). Here, we used wild-type and Ca V 3.2 knockout (Ca V 3.2 −/− ) mice to definitively test whether Ca V 3.2 moderates myogenic tone in mesenteric arteries via the Ca V 3.2-ryanodine receptor-BK Ca axis and whether this regulatory mechanism influences blood pressure regulation. Approach and Results— Using pressurized vessel myography, Ca V 3.2 −/− 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 Ca V 3.2 blocker, to either constrict arteries or suppress T-type currents in Ca V 3.2 −/− smooth muscle cells. The frequency of BK Ca -induced spontaneous transient outward K + currents dropped in wild-type but not in knockout arterial smooth muscle cells upon the pharmacological suppression of Ca V 3.2 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 Ca V 3.2 channel moderated myogenic constriction of resistance arteries, the blood pressure measurements of Ca V 3.2 −/− and wild-type animals were similar. Conclusions— Overall, our findings establish a negative feedback mechanism of the myogenic response in which Ca V 3.2 channel modulates downstream ryanodine receptor-BK Ca to hyperpolarize and relax arteries.
Feedback, Physiological, Male, Mice, Knockout, Myocytes, Smooth Muscle, Ryanodine Receptor Calcium Release Channel, Calcium Channel Blockers, Muscle, Smooth, Vascular, Mesenteric Arteries, Mice, Inbred C57BL, Vasodilation, Calcium Channels, T-Type, Vasoconstriction, Animals, Arterial Pressure, Female, Calcium Signaling, Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
Feedback, Physiological, Male, Mice, Knockout, Myocytes, Smooth Muscle, Ryanodine Receptor Calcium Release Channel, Calcium Channel Blockers, Muscle, Smooth, Vascular, Mesenteric Arteries, Mice, Inbred C57BL, Vasodilation, Calcium Channels, T-Type, Vasoconstriction, Animals, Arterial Pressure, Female, Calcium Signaling, Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 39 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |
