Smooth muscle Ca(2+) -activated and voltage-gated K+ channels modulate conducted dilation in rat isolated small mesenteric arteries.
OBJECTIVE: To assess the influence of blocking smooth muscle large conductance Ca(2+) -activated K+ channels and voltage-gated K+ channels on the conducted dilation to ACh and isoproterenol. MATERIALS AND METHODS: Rat mesenteric arteries were isolated with a bifurcation, triple-cannulated, press...
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| Format: | Journal article |
| Language: | English |
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2011
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| _version_ | 1797087471013462016 |
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| author | Beleznai, T Yarova, P Yuill, K Dora, K |
| author_facet | Beleznai, T Yarova, P Yuill, K Dora, K |
| author_sort | Beleznai, T |
| collection | OXFORD |
| description | OBJECTIVE: To assess the influence of blocking smooth muscle large conductance Ca(2+) -activated K+ channels and voltage-gated K+ channels on the conducted dilation to ACh and isoproterenol. MATERIALS AND METHODS: Rat mesenteric arteries were isolated with a bifurcation, triple-cannulated, pressurized and imaged using confocal microscopy. Phenylephrine was added to the superfusate to generate tone, and agonists perfused into a sidebranch to evoke local dilation and subsequent conducted dilation into the feed artery. RESULTS: Both ACh- and isoproterenol-stimulated local and conducted dilation with similar magnitudes of decay with distance along the feed artery (2000μm: ∼15% maximum dilation). The gap junction uncoupler carbenoxolone prevented both conducted dilation and intercellular spread of dye through gap junctions. IbTx, TEA or 4-AP, blockers of large conductance Ca(2+) -activated K+ channels and voltage-gated K+ channels, did not affect conducted dilation to either agonist. A combination of either IbTx or TEA with 4-AP markedly improved the extent of conducted dilation to both agonists (2000μm: >50% maximum dilation). The enhanced conducted dilation was reflected in the hyperpolarization to ACh (2000μm: Control, 4±1 mV, n = 3; TEA with 4-AP, 14±3mV, n=4), and was dependent on the endothelium. CONCLUSIONS: These data show that activated BK(Ca) and K(V) -channels serve to reduce the effectiveness of conducted dilation. |
| first_indexed | 2024-03-07T02:36:09Z |
| format | Journal article |
| id | oxford-uuid:a8dd1264-38b8-4c1a-a669-b3e2b53866b0 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:36:09Z |
| publishDate | 2011 |
| record_format | dspace |
| spelling | oxford-uuid:a8dd1264-38b8-4c1a-a669-b3e2b53866b02022-03-27T03:04:29ZSmooth muscle Ca(2+) -activated and voltage-gated K+ channels modulate conducted dilation in rat isolated small mesenteric arteries.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a8dd1264-38b8-4c1a-a669-b3e2b53866b0EnglishSymplectic Elements at Oxford2011Beleznai, TYarova, PYuill, KDora, KOBJECTIVE: To assess the influence of blocking smooth muscle large conductance Ca(2+) -activated K+ channels and voltage-gated K+ channels on the conducted dilation to ACh and isoproterenol. MATERIALS AND METHODS: Rat mesenteric arteries were isolated with a bifurcation, triple-cannulated, pressurized and imaged using confocal microscopy. Phenylephrine was added to the superfusate to generate tone, and agonists perfused into a sidebranch to evoke local dilation and subsequent conducted dilation into the feed artery. RESULTS: Both ACh- and isoproterenol-stimulated local and conducted dilation with similar magnitudes of decay with distance along the feed artery (2000μm: ∼15% maximum dilation). The gap junction uncoupler carbenoxolone prevented both conducted dilation and intercellular spread of dye through gap junctions. IbTx, TEA or 4-AP, blockers of large conductance Ca(2+) -activated K+ channels and voltage-gated K+ channels, did not affect conducted dilation to either agonist. A combination of either IbTx or TEA with 4-AP markedly improved the extent of conducted dilation to both agonists (2000μm: >50% maximum dilation). The enhanced conducted dilation was reflected in the hyperpolarization to ACh (2000μm: Control, 4±1 mV, n = 3; TEA with 4-AP, 14±3mV, n=4), and was dependent on the endothelium. CONCLUSIONS: These data show that activated BK(Ca) and K(V) -channels serve to reduce the effectiveness of conducted dilation. |
| spellingShingle | Beleznai, T Yarova, P Yuill, K Dora, K Smooth muscle Ca(2+) -activated and voltage-gated K+ channels modulate conducted dilation in rat isolated small mesenteric arteries. |
| title | Smooth muscle Ca(2+) -activated and voltage-gated K+ channels modulate conducted dilation in rat isolated small mesenteric arteries. |
| title_full | Smooth muscle Ca(2+) -activated and voltage-gated K+ channels modulate conducted dilation in rat isolated small mesenteric arteries. |
| title_fullStr | Smooth muscle Ca(2+) -activated and voltage-gated K+ channels modulate conducted dilation in rat isolated small mesenteric arteries. |
| title_full_unstemmed | Smooth muscle Ca(2+) -activated and voltage-gated K+ channels modulate conducted dilation in rat isolated small mesenteric arteries. |
| title_short | Smooth muscle Ca(2+) -activated and voltage-gated K+ channels modulate conducted dilation in rat isolated small mesenteric arteries. |
| title_sort | smooth muscle ca 2 activated and voltage gated k channels modulate conducted dilation in rat isolated small mesenteric arteries |
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