DIFFERENTIAL DISTRIBUTION AND FUNCTIONAL IMPACT OF BK CHANNEL BETA1 SUBUNITS ACROSS MESENTERIC, CORONARY AND DIFFERENT CEREBRAL ARTERIES OF THE RAT
| Autor: | Guruprasad Kuntamallappanavar, Alejandro M. Dopico, Anna N. Bukiya, Shivantika Bisen |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Male medicine.medical_specialty BK channel Contraction (grammar) Vascular smooth muscle Physiology Large-Conductance Calcium-Activated Potassium Channel beta Subunits Clinical Biochemistry Cerebral arteries Vasodilation Blood Pressure Article Muscle Smooth Vascular Rats Sprague-Dawley 03 medical and health sciences Physiology (medical) Internal medicine medicine Myocyte Animals Receptor Muscle Cells biology Chemistry Anatomy Cerebral Arteries Coronary Vessels Mesenteric Arteries Rats 030104 developmental biology medicine.anatomical_structure Endocrinology biology.protein Artery Muscle Contraction |
| Popis: | Large conductance, Ca2+ i- and voltage-gated K+ (BK) channels regulate myogenic tone and, thus, arterial diameter. In smooth muscle (SM), BK channels include channel-forming α and auxiliary β1 subunits. BK β1 increases the channel’s Ca2+ sensitivity, allowing BK channels to negatively feedback on depolarization-induced Ca2+ entry, oppose SM contraction and favor vasodilation. Thus, endothelial-independent vasodilation can be evoked though targeting of SM BK β1 by endogenous ligands, including lithocholate (LCA). Here, we investigated the expression of BK β1 across arteries of the cerebral and peripheral circulations, and the contribution of such expression to channel function and BK β1-mediated vasodilation. Data demonstrate that endothelium-independent, BK β1-mediated vasodilation by LCA is larger in coronary (CA) and basilar (BA) arteries than in anterior cerebral (ACA), middle cerebral (MCA), posterior cerebral (PCA), and mesenteric (MA) arteries, all arterial segments having a similar diameter. Thus, differential dilation occurs in extracranial arteries which are subjected to similar vascular pressure (CA vs. MA) and in arteries that irrigate different brain regions (BA vs. ACA, MCA, and PCA). SM BK channels from BA and CA displayed increased basal activity and LCA responses, indicating increased BK β1 functional presence. Indeed, in the absence of detectable changes in BK α, BA and CA myocytes showed an increased location of BK β1 in the plasmalemma/subplasmalemma. Moreover, these myocytes distinctly showed increased BK β1 messenger RNA (mRNA) levels. Supporting a major role of enhanced BK β1 transcripts in artery dilation, LCA-induced dilation of MCA transfected with BK β1 complementary DNA (cDNA) was as high as LCA-induced dilation of untransfected BA or CA. |
| Databáze: | OpenAIRE |
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