PMID- 11903131
OWN - NLM
STAT- MEDLINE
DCOM- 20020605
LR  - 20191210
IS  - 0001-6772 (Print)
IS  - 0001-6772 (Linking)
VI  - 173
IP  - 4
DP  - 2001 Dec
TI  - Cyclopiazonic acid and thapsigargin reduce Ca2+ influx in frog skeletal muscle 
      fibres as a result of Ca2+ store depletion.
PG  - 391-9
AB  - We have investigated the influence of the sarcoplasmic reticulum (SR) Ca2+ 
      content on the retrograde control of skeletal muscle L-type Ca2+ channels 
      activity by ryanodine receptors (RyR). The effects of cyclopiazonic acid (CPA) 
      and thapsigargin (TG), two structurally unrelated inhibitors of SR 
      Ca(2+)-adenosine triphosphatase (ATPase), were examined on the SR Ca2+ content, 
      the calcium current and contraction in single frog semitendinosus fibres using 
      the double mannitol-gap technique. At moderate concentrations that only partially 
      inhibited Ca2+ sequestration by the SR, CPA (2-4 microM) induces a concentration 
      dependent depression of contraction and Ca2+ current amplitudes. When Ba2+ is the 
      charge carrier, the inward current is not changed by CPA suggesting that this 
      Ca(2+)-pump inhibitor does not directly affect dihydropyridine Ca2+ channels. 
      Similar effects were obtained with TG (1-5 microM). Changes in Ca2+ currents and 
      contraction were accompanied by a reduced Ca2+ loading of the SR. We attribute 
      the modulation of the Ca2+ current to the selective inhibition of the SR Ca2+ 
      ATPase, resulting in a decreased Ca2+ release and thereby a reduced activation of 
      calcium inward currents. This is therefore taken to represent a calcium 
      release-dependent modulation of skeletal muscle L-type Ca2+ channels.
FAU - Meme, W
AU  - Meme W
AD  - Developpement et Physiologie des Structures Contractiles, CNRS UMR 6018, Faculte 
      des Sciences et des Techniques, Nantes, France.
FAU - Leoty, C
AU  - Leoty C
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Acta Physiol Scand
JT  - Acta physiologica Scandinavica
JID - 0370362
RN  - 0 (Calcium Channels, L-Type)
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (Indoles)
RN  - 24GP945V5T (Barium)
RN  - 67526-95-8 (Thapsigargin)
RN  - EC 3.6.3.8 (Sarcoplasmic Reticulum Calcium-Transporting ATPases)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - SY7Q814VUP (Calcium)
RN  - X9TLY4580Z (cyclopiazonic acid)
SB  - IM
MH  - Animals
MH  - Barium/pharmacokinetics
MH  - Calcium/*metabolism
MH  - Calcium Channels, L-Type/metabolism
MH  - Calcium-Transporting ATPases/metabolism
MH  - Enzyme Inhibitors/*pharmacology
MH  - In Vitro Techniques
MH  - Indoles/*pharmacology
MH  - Membrane Potentials/drug effects/physiology
MH  - Muscle Contraction/physiology
MH  - Muscle Fibers, Skeletal/drug effects/*metabolism
MH  - Muscle, Skeletal/cytology/physiology
MH  - Patch-Clamp Techniques
MH  - Rana esculenta
MH  - Sarcoplasmic Reticulum/metabolism
MH  - Sarcoplasmic Reticulum Calcium-Transporting ATPases
MH  - Thapsigargin/*pharmacology
EDAT- 2002/03/21 10:00
MHDA- 2002/06/06 10:01
CRDT- 2002/03/21 10:00
PHST- 2002/03/21 10:00 [pubmed]
PHST- 2002/06/06 10:01 [medline]
PHST- 2002/03/21 10:00 [entrez]
AID - 918 [pii]
AID - 10.1046/j.1365-201X.2001.00918.x [doi]
PST - ppublish
SO  - Acta Physiol Scand. 2001 Dec;173(4):391-9. doi: 10.1046/j.1365-201X.2001.00918.x.