G protein effects on Ca2+ release and excitation-contraction coupling in skeletal muscle fibers

L. Carney-Anderson, S. K. Donaldson

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Skeletal muscle excitation-contraction (EC) coupling may involve secondary mechanisms, such as those involving G proteins. The aim of this study was to identify possible G protein effects on sarcoplasmic reticulum (SR) Ca 2+ release, in general, and on voltage-dependent EC coupling, in particular. Effects of guanosine 5'-O-(3-thiotriphosphate) (GTPγS) were studied using a single peeled rabbit skeletal muscle fiber preparation that is capable of releasing SR Ca 2+ in response to transverse tubule (TT) depolarization. Because of possible nonspecific and residual effects of 200 μM GTPγS, a lower concentration of 50 μM GTPγS was used to stimulate G proteins in the peeled fiber system. Under conditions for steady state (resting) polarization of TT, GTPγS rarely elicited SR Ca 2+ release. When the TTs are in steady- state (resting) depolarization, 50 μM GTPγS or GTP elicited SR Ca 2+ release and associated tension transients in only 69% of fibers tested. In contrast, GTPγS always augmented Ca 2+ release during TT depolarization- induced EC coupling. These results indicate the presence of at least two excitatory G proteins for SR Ca 2+ release, only one of which is a modulator albeit nonessential, of peeled fiber EC coupling.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume267
Issue number4 part 1
StatePublished - 1994

Fingerprint

Excitation Contraction Coupling
Skeletal Muscle Fibers
Sarcoplasmic Reticulum
GTP-Binding Proteins
Muscle
Depolarization
Fibers
Guanosine 5'-O-(3-Thiotriphosphate)
Guanosine Triphosphate
Modulators
Muscle Contraction
Polarization
Skeletal Muscle
Rabbits
Electric potential

Keywords

  • caffeine
  • guanosine 5'-O-(2-thiodiphosphate)
  • guanosine 5'-O-(3- thiotriphosphate
  • peeled skeletal muscle fibers
  • rabbit
  • sarcoplasmic reticulum calcium release

Cite this

G protein effects on Ca2+ release and excitation-contraction coupling in skeletal muscle fibers. / Carney-Anderson, L.; Donaldson, S. K.

In: American Journal of Physiology - Cell Physiology, Vol. 267, No. 4 part 1, 1994.

Research output: Contribution to journalArticle

@article{081e396701884202b8e3ea38f90aab41,
title = "G protein effects on Ca2+ release and excitation-contraction coupling in skeletal muscle fibers",
abstract = "Skeletal muscle excitation-contraction (EC) coupling may involve secondary mechanisms, such as those involving G proteins. The aim of this study was to identify possible G protein effects on sarcoplasmic reticulum (SR) Ca 2+ release, in general, and on voltage-dependent EC coupling, in particular. Effects of guanosine 5'-O-(3-thiotriphosphate) (GTPγS) were studied using a single peeled rabbit skeletal muscle fiber preparation that is capable of releasing SR Ca 2+ in response to transverse tubule (TT) depolarization. Because of possible nonspecific and residual effects of 200 μM GTPγS, a lower concentration of 50 μM GTPγS was used to stimulate G proteins in the peeled fiber system. Under conditions for steady state (resting) polarization of TT, GTPγS rarely elicited SR Ca 2+ release. When the TTs are in steady- state (resting) depolarization, 50 μM GTPγS or GTP elicited SR Ca 2+ release and associated tension transients in only 69{\%} of fibers tested. In contrast, GTPγS always augmented Ca 2+ release during TT depolarization- induced EC coupling. These results indicate the presence of at least two excitatory G proteins for SR Ca 2+ release, only one of which is a modulator albeit nonessential, of peeled fiber EC coupling.",
keywords = "caffeine, guanosine 5'-O-(2-thiodiphosphate), guanosine 5'-O-(3- thiotriphosphate, peeled skeletal muscle fibers, rabbit, sarcoplasmic reticulum calcium release",
author = "L. Carney-Anderson and Donaldson, {S. K.}",
year = "1994",
language = "English (US)",
volume = "267",
journal = "American Journal of Physiology - Cell Physiology",
issn = "0363-6143",
publisher = "American Physiological Society",
number = "4 part 1",

}

TY - JOUR

T1 - G protein effects on Ca2+ release and excitation-contraction coupling in skeletal muscle fibers

AU - Carney-Anderson, L.

AU - Donaldson, S. K.

PY - 1994

Y1 - 1994

N2 - Skeletal muscle excitation-contraction (EC) coupling may involve secondary mechanisms, such as those involving G proteins. The aim of this study was to identify possible G protein effects on sarcoplasmic reticulum (SR) Ca 2+ release, in general, and on voltage-dependent EC coupling, in particular. Effects of guanosine 5'-O-(3-thiotriphosphate) (GTPγS) were studied using a single peeled rabbit skeletal muscle fiber preparation that is capable of releasing SR Ca 2+ in response to transverse tubule (TT) depolarization. Because of possible nonspecific and residual effects of 200 μM GTPγS, a lower concentration of 50 μM GTPγS was used to stimulate G proteins in the peeled fiber system. Under conditions for steady state (resting) polarization of TT, GTPγS rarely elicited SR Ca 2+ release. When the TTs are in steady- state (resting) depolarization, 50 μM GTPγS or GTP elicited SR Ca 2+ release and associated tension transients in only 69% of fibers tested. In contrast, GTPγS always augmented Ca 2+ release during TT depolarization- induced EC coupling. These results indicate the presence of at least two excitatory G proteins for SR Ca 2+ release, only one of which is a modulator albeit nonessential, of peeled fiber EC coupling.

AB - Skeletal muscle excitation-contraction (EC) coupling may involve secondary mechanisms, such as those involving G proteins. The aim of this study was to identify possible G protein effects on sarcoplasmic reticulum (SR) Ca 2+ release, in general, and on voltage-dependent EC coupling, in particular. Effects of guanosine 5'-O-(3-thiotriphosphate) (GTPγS) were studied using a single peeled rabbit skeletal muscle fiber preparation that is capable of releasing SR Ca 2+ in response to transverse tubule (TT) depolarization. Because of possible nonspecific and residual effects of 200 μM GTPγS, a lower concentration of 50 μM GTPγS was used to stimulate G proteins in the peeled fiber system. Under conditions for steady state (resting) polarization of TT, GTPγS rarely elicited SR Ca 2+ release. When the TTs are in steady- state (resting) depolarization, 50 μM GTPγS or GTP elicited SR Ca 2+ release and associated tension transients in only 69% of fibers tested. In contrast, GTPγS always augmented Ca 2+ release during TT depolarization- induced EC coupling. These results indicate the presence of at least two excitatory G proteins for SR Ca 2+ release, only one of which is a modulator albeit nonessential, of peeled fiber EC coupling.

KW - caffeine

KW - guanosine 5'-O-(2-thiodiphosphate)

KW - guanosine 5'-O-(3- thiotriphosphate

KW - peeled skeletal muscle fibers

KW - rabbit

KW - sarcoplasmic reticulum calcium release

UR - http://www.scopus.com/inward/record.url?scp=0028011639&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028011639&partnerID=8YFLogxK

M3 - Article

C2 - 7943272

AN - SCOPUS:0028011639

VL - 267

JO - American Journal of Physiology - Cell Physiology

JF - American Journal of Physiology - Cell Physiology

SN - 0363-6143

IS - 4 part 1

ER -