PMID- 7585826
OWN - NLM
STAT- MEDLINE
DCOM- 19951226
LR  - 20191210
IS  - 0008-6363 (Print)
IS  - 0008-6363 (Linking)
VI  - 30
IP  - 3
DP  - 1995 Sep
TI  - Effects of thapsigargin on aequorin-injected and skinned preparations of ferret 
      ventricular muscles.
PG  - 357-62
AB  - OBJECTIVE: We investigated the effects of thapsigargin (TG) (0.1-1 microM) on the 
      relation between intracellular Ca2+ concentration and tension in ferret papillary 
      muscles using aequorin-injected and skinned preparations. METHODS: Aequorin was 
      injected into the superficial cells of ferret papillary muscles; the Ca2+ signals 
      of aequorin and tension in twitch and those with the application of 15 mM 
      caffeine were simultaneously measured. The alteration of Ca2+ sensitivity of the 
      contractile elements was examined by measuring the pCa-tension relation in 
      Triton-X-treated skinned preparations. RESULTS: TG decreased the peak of the Ca2+ 
      signal accompanied by a prolonged decay time. However, the tension was scarcely 
      altered even at 1 microM TG. TG inhibited the caffeine-induced Ca2+ signal. 
      Prolongation of decay of the Ca2+ signal by TG in twitch was further enhanced by 
      isoprenaline (10 nM). The pCa-tension relation of the skinned preparation was 
      slightly but significantly shifted to the right by TG. CONCLUSIONS: The apparent 
      dissociation of the effects of TG on the Ca2+ signal and tension in intact 
      preparations is not a result of alteration of the Ca2+ sensitivity of the 
      myofilaments. The effects of TG in multicellular preparations are probably 
      limited to the outer layer of the preparation. The slower time course of the Ca2+ 
      signal induced by TG is due to the inhibition of Ca2+ uptake by sarcoplasmic 
      reticulum, which is more significantly observed when the intracellular Ca2+ 
      transient is increased by isoprenaline.
FAU - Tanaka, T
AU  - Tanaka T
AD  - Department of Physiology, Jikei University School of Medicine, Tokyo, Japan.
FAU - Komukai, K
AU  - Komukai K
FAU - Kawai, M
AU  - Kawai M
FAU - Tanaka, E
AU  - Tanaka E
FAU - Kurihara, S
AU  - Kurihara S
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Cardiovasc Res
JT  - Cardiovascular research
JID - 0077427
RN  - 0 (Cardiotonic Agents)
RN  - 0 (Terpenes)
RN  - 3G6A5W338E (Caffeine)
RN  - 50934-79-7 (Aequorin)
RN  - 67526-95-8 (Thapsigargin)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - L628TT009W (Isoproterenol)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Aequorin/*pharmacology
MH  - Animals
MH  - Caffeine/pharmacology
MH  - Calcium/metabolism
MH  - Calcium-Transporting ATPases/*antagonists & inhibitors
MH  - Cardiotonic Agents/pharmacology
MH  - Ferrets
MH  - In Vitro Techniques
MH  - Isoproterenol/pharmacology
MH  - Papillary Muscles/*drug effects/metabolism
MH  - Sarcoplasmic Reticulum/drug effects/metabolism
MH  - Terpenes/*pharmacology
MH  - Thapsigargin
EDAT- 1995/09/01 00:00
MHDA- 1995/09/01 00:01
CRDT- 1995/09/01 00:00
PHST- 1995/09/01 00:00 [pubmed]
PHST- 1995/09/01 00:01 [medline]
PHST- 1995/09/01 00:00 [entrez]
AID - 0008-6363(95)00053-4 [pii]
PST - ppublish
SO  - Cardiovasc Res. 1995 Sep;30(3):357-62.