PMID- 9334880
OWN - NLM
STAT- MEDLINE
DCOM- 19971121
LR  - 20190725
IS  - 0021-5198 (Print)
IS  - 0021-5198 (Linking)
VI  - 75
IP  - 1
DP  - 1997 Sep
TI  - Is guanosine-5'-triphosphate involved in calcium-activation of contractile 
      proteins in vascular smooth muscle?
PG  - 1-12
AB  - Isometric tension was measured to investigate the effects of 
      guanosine-5'-triphosphate (GTP) on the run-down of myofilament Ca2+ sensitivity 
      in isolated rat mesenteric arteries permeabilized with beta-escin. The Ca2+ 
      sensitivity assessed by the EC50 value for the Ca2+ (0.1-100 microM)-tension 
      relationship progressively runs down in the control strips, while it was 
      well-preserved for 5-successive Ca2+ applications in the presence of GTP (50 
      microM); no significant difference was found in the Ca2+ sensitivity observed 
      with the 1st Ca2+ application between the control and GTP-treated strips. 
      Guanosine-5'-(2-O-thio) diphosphate (GDP beta S, 100 microM) significantly 
      decreased the Ca2+ sensitivity with the 1st Ca2+ application and eliminated the 
      run-down of Ca2+ sensitivity. GTP (3-150 microM), applied to the strips 
      submaximally precontracted with Ca2+, had a little effect on the Ca2+ 
      contractions in the early stage of experiments, but dramatically enhanced the 
      Ca2+ contractions in their later stage; its latter effect was mimicked by 
      guanosine-5'-(3-O-thio) triphosphate (GTP gamma S) and reversed by GDP beta S 
      (100 microM). The results suggest: 1) loss of endogenous GTP following 
      permeabilization is involved in the run-down of Ca2+ sensitivity; and 2) 
      activation of G-proteins is involved in Ca(2+)-activation of contractile 
      proteins.
FAU - Akata, T
AU  - Akata T
AD  - Department of Anesthesiology, Washington University School of Medicine, St. 
      Louis, MO 63110-1093, USA.
FAU - Boyle, W A 3rd
AU  - Boyle WA 3rd
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Japan
TA  - Jpn J Pharmacol
JT  - Japanese journal of pharmacology
JID - 2983305R
RN  - 0 (Calcium Channels)
RN  - 0 (Contractile Proteins)
RN  - 146-91-8 (Guanosine Diphosphate)
RN  - 6805-41-0 (Escin)
RN  - 86-01-1 (Guanosine Triphosphate)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Calcium/*pharmacology/physiology
MH  - Calcium Channels/drug effects
MH  - Cell Membrane Permeability/drug effects
MH  - Contractile Proteins/*drug effects
MH  - Escin/pharmacology
MH  - Guanosine Diphosphate/pharmacology
MH  - Guanosine Triphosphate/*pharmacology
MH  - In Vitro Techniques
MH  - Male
MH  - Mesenteric Arteries/drug effects/physiology
MH  - Muscle Contraction/drug effects
MH  - Muscle, Smooth, Vascular/*drug effects/physiology
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Time Factors
EDAT- 1997/10/23 22:31
MHDA- 2001/03/28 10:01
CRDT- 1997/10/23 22:31
PHST- 1997/10/23 22:31 [pubmed]
PHST- 2001/03/28 10:01 [medline]
PHST- 1997/10/23 22:31 [entrez]
AID - 10.1254/jjp.75.1 [doi]
PST - ppublish
SO  - Jpn J Pharmacol. 1997 Sep;75(1):1-12. doi: 10.1254/jjp.75.1.