PMID- 1297859
OWN - NLM
STAT- MEDLINE
DCOM- 19930506
LR  - 20190827
IS  - 0021-521X (Print)
IS  - 0021-521X (Linking)
VI  - 42
IP  - 6
DP  - 1992
TI  - An analysis of post-contracture potentiation in frog twitch skeletal muscle.
PG  - 917-28
AB  - Post-tetanic potentiation (PTP) was mimicked by post-contracture potentiation 
      (PCP) in the twitch muscle of frog. A marked PCP was observed in small bundles of 
      semitendinosus muscle in tetrodotoxin (TTX)-containing solution under current 
      clamp condition. Contractures were induced by a constant depolarizing current 
      pulse of 1 s every 5 min. Each contracture (C) was preceded and followed by a 
      twitch-corresponding short contracture, T1 and T2, with an interval of 2 s. The 
      ratio of twitch height, T2/T1, was measured and compared under various 
      conditions. In TTX-containing Ringer solution, T2/T1 depended on magnitude of 
      both T and C. When T2/T1 was plotted against C/T1 a quasi-linear relationship was 
      found. The slope of the curve was 0.076 and was found to decrease when the 
      duration of T was increased to 1 s. In TTX-containing solution, addition of 2 mM 
      Ba2+ or 1 mM caffeine potentiated T as well as C but decreased T2/T1 markedly. 
      Similar effects were observed when Na+ was replaced with TEA+ or when bath 
      temperature was lowered from 20 to 8 degrees C. In all cases T2/T1 vs. C/T1 curve 
      was shifted to the left and downwards. It was considered that these results could 
      be attributable to an elevation of the resting Ca2+ concentration in the 
      sarcoplasm. Thus the phenomenon of PCP probably reflects the time course of Ca2+ 
      transients in the conditioning contracture C.
FAU - Kawata, H
AU  - Kawata H
AD  - Department of Physiology, School of Medicine, Fukuoka University, Japan.
FAU - Hatae, J
AU  - Hatae J
LA  - eng
PT  - Journal Article
PL  - Japan
TA  - Jpn J Physiol
JT  - The Japanese journal of physiology
JID - 2985184R
RN  - 0 (Tetraethylammonium Compounds)
RN  - 24GP945V5T (Barium)
RN  - 3G6A5W338E (Caffeine)
RN  - 4368-28-9 (Tetrodotoxin)
RN  - 66-40-0 (Tetraethylammonium)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Action Potentials
MH  - Animals
MH  - Barium/pharmacology
MH  - Caffeine/pharmacology
MH  - Calcium/metabolism
MH  - Electric Stimulation
MH  - In Vitro Techniques
MH  - Muscle Contraction/drug effects/*physiology
MH  - Ranidae
MH  - Temperature
MH  - Tetraethylammonium
MH  - Tetraethylammonium Compounds/pharmacology
MH  - Tetrodotoxin
EDAT- 1992/01/01 00:00
MHDA- 1992/01/01 00:01
CRDT- 1992/01/01 00:00
PHST- 1992/01/01 00:00 [pubmed]
PHST- 1992/01/01 00:01 [medline]
PHST- 1992/01/01 00:00 [entrez]
AID - 10.2170/jjphysiol.42.917 [doi]
PST - ppublish
SO  - Jpn J Physiol. 1992;42(6):917-28. doi: 10.2170/jjphysiol.42.917.