PMID- 8981073
OWN - NLM
STAT- MEDLINE
DCOM- 19970401
LR  - 20191210
IS  - 0306-3623 (Print)
IS  - 0306-3623 (Linking)
VI  - 27
IP  - 7
DP  - 1996 Oct
TI  - Cardiac mechanical and electrophysiologic modulations of guinea-pig by caffeine 
      and thapsigargin.
PG  - 1227-35
AB  - 1. The effects of caffeine and thapsigargin on the contractile force and the 
      action potential in guinea-pig papillary muscles were examined. 2. Caffeine (1 to 
      10 mM) initially increased contractile force in a concentration-dependent manner. 
      Subsequently, 1 mM caffeine decreased it as compared with precaffeine level (but 
      not significantly). At 5 mM or 10 mM, caffeine also decreased contractile force, 
      but the decrease was still positive as compared with control level. 3. Exchange 
      to low [Ca]o (0.9 mM) or high [K]o (8 mM) decreased steady-state value during 
      exposure to 1 mM caffeine. Addition of 1 microM thapsigargin (TG) decreased the 
      steady-state value during exposure to 1 mM caffeine, but enhanced it with 5 mM 
      and 10 mM caffeine. TG (1 microM) alone increased the force. 4. In 
      electrophysiologic, studies, caffeine shortened the action potential duration 
      (APD) in a concentration-dependent manner. In the presence of caffeine (1 mM), 
      high [K]o shortened APD and decreased the action potential amplitude and resting 
      potential. 5. These results suggest that in the presence of caffeine and/or 
      thapsigargin calcium overload might not occur in the left ventricular papillary 
      muscles of the guinea-pig heart.
FAU - Nario, K
AU  - Nario K
AD  - Department of Pharmacology, Nara Medical University, Japan.
FAU - Satoh, H
AU  - Satoh H
LA  - eng
PT  - Journal Article
PL  - England
TA  - Gen Pharmacol
JT  - General pharmacology
JID - 7602417
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (Phosphodiesterase Inhibitors)
RN  - 3G6A5W338E (Caffeine)
RN  - 67526-95-8 (Thapsigargin)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - RWP5GA015D (Potassium)
SB  - IM
MH  - Action Potentials/drug effects/physiology
MH  - Animals
MH  - Caffeine/*pharmacology
MH  - Calcium-Transporting ATPases/*antagonists & inhibitors
MH  - Electrophysiology
MH  - Enzyme Inhibitors/*pharmacology
MH  - Guinea Pigs
MH  - Heart/drug effects/*physiology
MH  - In Vitro Techniques
MH  - Myocardial Contraction/*drug effects
MH  - Papillary Muscles/drug effects
MH  - Phosphodiesterase Inhibitors/*pharmacology
MH  - Potassium/pharmacology
MH  - Sarcoplasmic Reticulum/drug effects/enzymology
MH  - Thapsigargin/*pharmacology
EDAT- 1996/10/01 00:00
MHDA- 1996/10/01 00:01
CRDT- 1996/10/01 00:00
PHST- 1996/10/01 00:00 [pubmed]
PHST- 1996/10/01 00:01 [medline]
PHST- 1996/10/01 00:00 [entrez]
AID - 0306362395021388 [pii]
AID - 10.1016/0306-3623(95)02138-8 [doi]
PST - ppublish
SO  - Gen Pharmacol. 1996 Oct;27(7):1227-35. doi: 10.1016/0306-3623(95)02138-8.