The role of chloride transport in the control of the membrane potential in skeletal muscle — Theory and experiment

2009 ◽  
Vol 143 (1-2) ◽  
pp. 18-25 ◽  
Author(s):  
Jill Gallaher ◽  
Martin Bier ◽  
Jan Siegenbeek van Heukelom
Keyword(s):  
Skeletal Muscle ◽  
Membrane Potential ◽  
Chloride Transport ◽  
Theory And Experiment

Myogenic contraction in rat skeletal muscle arterioles: smooth muscle membrane potential and Ca2+ signaling

2005 ◽  
Vol 289 (4) ◽  
pp. H1326-H1334 ◽  
Author(s):  
Neela Kotecha ◽  
Michael A. Hill
Keyword(s):  
Skeletal Muscle ◽  
Membrane Potential ◽  
Cyclopiazonic Acid ◽  
Intraluminal Pressure ◽  
Muscle Membrane ◽  
Myogenic Tone ◽  
Pharmacological Interventions ◽  
Smooth Muscle Membrane ◽  
Complex Relationships

The present studies examined relationships between intraluminal pressure, membrane potential ( Em), and myogenic tone in skeletal muscle arterioles. Using pharmacological interventions targeting Ca2+ entry/release mechanisms, these studies also determined the role of Ca2+ pathways and Em in determining steady-state myogenic constriction. Studies were conducted in isolated and cannulated arterioles under zero flow. Increasing intraluminal pressure (0–150 mmHg) resulted in progressive membrane depolarization (−55.3 ± 4.1 to −29.4 ± 0.7 mV) that exhibited a sigmoidal relationship between extent of myogenic constriction and Em. Thus, despite further depolarization, at pressures >70 mmHg, little additional vasoconstriction occurred. This was not due to an inability of voltage-operated Ca2+ channels to be activated as KCl (75 mM) evoked depolarization and vasoconstriction at 120 mmHg. Nifedipine (1 μM) and cyclopiazonic acid (30 μM) significantly attenuated established myogenic tone, whereas inhibition of inositol 1,4,5-trisphosphate-mediated Ca2+ release/entry by 2-aminoethoxydiphenylborate (50 μM) had little effect. Combinations of the Ca2+ entry blockers with the sarcoplasmic reticulum (SR) inhibitor caused a total loss of tone, suggesting that while depolarization-mediated Ca2+ entry makes a significant contribution to myogenic tone, an interaction between Ca2+ entry and SR Ca2+ release is necessary for maintenance of myogenic constriction. In contrast, none of the agents, in combination or alone, altered Em, demonstrating the downstream role of Ca2+ mobilization relative to changes in Em. Large-conductance Ca2+-activated K+ channels modulated Em to exert a small effect on myogenic tone, and consistent with this, skeletal muscle arterioles appeared to show an inherently steep relationship between Em and extent of myogenic tone. Collectively, skeletal muscle arterioles exhibit complex relationships between Em, Ca2+ availability, and myogenic constriction that impact on the tissue's physiological function.

MIOPATIA MUSCULAR ESQUELÉTICA INDUZIDA PELA INSUFICIÊNCIA CARDÍACA DE ETIOLOGIA HIPERTENSIVA: PAPEL TERAPÊUTICO DO TREINAMENTO FÍSICO AERÓBIOHYPERTENSIVE HEART FAILURE-INDUCED SKELETAL MUSCLE MYOPATHY: THERAPEUTIC ROLE OF AEROBIC EXERCISE TRAININGRESUMOA insuficiência cardíaca (IC) é a via final comum da maioria das doenças que acometem o coração. Entre os fatores de risco conhecidos, a hipertensão arterial (HA) é a doença mais frequentemente associada à IC. Caracterizada pela intolerância ao exercício, a IC promove disfunção cardíaca e alterações intrínsecas musculares envolvidas na redução da capacidade física. Várias anormalidades do músculo esquelético têm sido descritas em pacientes e animais com IC, incluindo atrofia, fibrose, mudança na composição dos tipos de fibras, rarefação microvascular e reduzida capacidade de oxidação. Por outro lado, o treinamento físico aeróbio (TFA) vem sendo utilizado como uma importante terapia não farmacológica para a prevenção e o tratamento da IC; em parte, por melhorar a função endotelial e a perfusão coronária, diminuir a resistência vascular periférica e induzir o remodelamento das células musculares cardíacas e esqueléticas, levando ao aumento da captação de oxigênio e resistência à fadiga. Os mecanismos e vias de sinalização intracelular envolvidas nas anormali

2020 ◽  
Vol 30 (2) ◽  
pp. 239-247
Author(s):  
Bruno Rocha de Avila Pelozin ◽  
◽  
Larissa Ferreira-Santos ◽  
Luis Felipe Rodrigues ◽  
Edilamar Menezes de Oliveira ◽  
...  
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Aerobic Exercise ◽  
Therapeutic Role ◽  
Insuficiencia Cardiaca
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