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March 1, 1994AJP Heart and Circulatory Physiology

Characteristics and origin of myogenic response in isolated gracilis muscle arterioles

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Population

Isolated first-, second-, and third-order rat gracilis muscle arterioles

Comparison

Step increases in perfusion pressure and… vs Ca-free solution with sodium nitroprusside…

Design

Preclinical

Authors

DSDong SunShanxi Medical UniversityGKGabor KaleySemmelweis UniversityÁKÁkos KollerVascular Medicine

Discussion

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Implication

Supports myogenic tone in rat skeletal muscle arterioles; leaves open translation to human microvascular regulation.

Key Points

  • To characterize the vascular myogenic response to changes in intravascular pressure across different orders of isolated skeletal muscle arterioles under no-flow conditions.
  • Isolated and cannulated first-, second-, and third-order arterioles from rat gracilis muscle under no-flow conditions.
  • Measured vessel diameter changes across perfusion pressure steps from 20 to 160 mmHg under active conditions and passive conditions using a Ca2+-free solution with 10^-4 M sodium nitroprusside.
  • Evaluated endothelial and vascular smooth muscle contributions using acetylcholine (10^-6 M) and sodium nitroprusside (5 x 10^-8 M) before and after mechanical endothelial denudation.
  • Step increases in perfusion pressure elicited active tone and vasoconstriction across all vessel orders, demonstrating an inverse pressure-diameter relationship in physiological pressure ranges.
  • Steady-state active versus passive diameters were 76.9 ± 1.6 vs. 161.8 ± 3.2 µm for 1st-order (at 100 mmHg), 32.3 ± 1.1 vs. 76.0 ± 1.7 µm for 2nd-order (at 80 mmHg), and 22.3 ± 3.2 vs. 47.6 ± 2.2 µm for 3rd-order arterioles (at 50 mmHg), with maximum constriction reaching approximately 60% of passive diameter.
  • Endothelial removal abolished dilation to acetylcholine but maintained responsiveness to sodium nitroprusside.

Structured PICO

P
Population
Isolated first-, second-, and third-order rat gracilis muscle arterioles
I
Intervention
Step increases in perfusion pressure (from 20 to 160 mmHg) and endothelium removal
C
Comparator
Ca(2+)-free solution with sodium nitroprusside (for passive diameter); intact endothelium
O
Outcome
Vascular diameter (active tone and constriction)surrogate

Isolated rat gracilis muscle arterioles demonstrate an intrinsic myogenic constrictor response to increased intravascular pressure.

Cite This Study

Sun et al. (1994) studied this question.

synapsesocial.com/papers/6a6faf7bf44fa9f079dd284bhttps://doi.org/10.1152/ajpheart.1994.266.3.h1177
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Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

  1. 1Characteristics and origin of myogenic response in isolated mesenteric arterioles1992 · 103 citations
  2. 2Myogenic response and wall mechanics of arterioles1989 · 57 citations
  3. 3Myogenic response gradient in an arteriolar network1993 · 162 citations
  4. 4Endothelial independence of myogenic response in isolated skeletal muscle arterioles1991 · 124 citations
  5. 5Myogenic responses of isolated arterioles: test for a rate-sensitive mechanism1990 · 87 citations