Synapse
⌘+K
Synapse
PulseExploreClubsResearchersJournals
Instagram
HomeClubsExplore
January 1, 1988The Japanese Journal of PhysiologyOpen Access

Effects of mechanical stretch on the membrane potential of guinea pig ventricular muscles.

View Full Paper
Ask AI
Bookmark
Share

Why the study?

Does mechanical stretch alter the membrane potential and ultrastructure in isolated guinea pig ventricular papillary muscles?

Population

Isolated ventricular papillary muscles of guinea pigs

Comparison

Stepwise mechanical stretch from slack length to… vs Slack length (90% of Lmax)

Design

Preclinical

Authors

ANAkira NakagawaMAMakoto AritaTSTatsuo Shimada

Discussion

Loading...

Member takes

Overview

These guinea pig findings should not yet change practice; leaves open stretch-severity effects on human ventricular electrophysiology.

Key Points

  • To examine how mechanical stretch affects membrane potentials and ultrastructure of guinea pig ventricular muscles.
  • Isolated ventricular papillary muscles were stretched stepwise from slack length to severe stretch.
  • Electrical stimulation at 0.5 Hz and recordings of membrane potentials were taken under varying potassium and calcium concentrations.
  • Electron microscopy was used to assess structural changes in the sarcoplasmic reticulum.
  • Mild to moderate stretch caused a 6 mV depolarization, while severe stretch led to a 5 mV hyperpolarization.
  • Alterations in potassium conductance contributed significantly to changes in resting potential with varying extracellular calcium concentrations.
  • Sarcoplasmic reticulum showed structural disarrangement with severe stretch, unlike the intact structure observed with mild to moderate stretches.

Structured PICO

Does mechanical stretch alter the membrane potential and ultrastructure in isolated guinea pig ventricular papillary muscles?

P
Population
Isolated ventricular papillary muscles of guinea pigs
I
Intervention
Stepwise mechanical stretch from slack length (90% of Lmax) to 100% (mild), 110-120% (moderate), and 130-140% of Lmax (severe)
C
Comparator
Slack length (90% of Lmax)
O
Outcome
Membrane potential (resting potential and maximum rate of rise of action potential) and ultrastructuresurrogate

Mechanical stretch induces severity-dependent changes in resting membrane potential in guinea pig ventricular muscles, with severe stretch causing hyperpolarization likely mediated by calcium release from the sarcoplasmic reticulum.

Cite This Study

Nakagawa et al. (1988) studied this question.

synapsesocial.com/papers/6a762f11b52b7ee7dcfbe4cbhttps://doi.org/10.2170/jjphysiol.38.819
View Full Paper
Ask AI
Bookmark
Share

Also Consider

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

  1. 1Factors related to the low resting membrane potentials of diseased human atrial muscles.1987 · 21 citations
  2. 2Ryanodine modification of cardiac muscle responses to potassium-free solutions. Evidence for inhibition of sarcoplasmic reticulum calcium release.1983 · 189 citations
  3. 3Properties of single calcium‐activated potassium channels in cultured rat muscle1982 · 715 citations
  4. 4Single channel analysis of the inward rectifier K current in the rabbit ventricular cells.1983 · 107 citations
  5. 5Action of caffeine on calcium transport by isolated fractions of myofibrils, mitochondria, and sarcoplasmic reticulum from rabbit heart.1978 · 79 citations