PMID- 9634642
OWN - NLM
STAT- MEDLINE
DCOM- 19980826
LR  - 20191210
IS  - 1043-6618 (Print)
IS  - 1043-6618 (Linking)
VI  - 37
IP  - 4
DP  - 1998 Apr
TI  - Different aspects of the effects of thapsigargin on automatism, contractility and 
      responsiveness to phenylephrine in cardiac preparations from rats and guinea 
      pigs.
PG  - 273-80
AB  - Sarcoplasmic reticulum (SR) Ca(2+)-ATPase play a very important role in 
      excitation-contraction coupling in the heart. The effects of thapsigargin (TG), a 
      selective inhibitor of SR Ca(2+)-ATPase in the heart muscle, on automatism and 
      contractility of the rat and guinea pig heart were examined. Experiments were 
      performed on isolated right auricula and right ventricle papillary muscle. The 
      following parameters were registered: force of contraction (Fc); rate of rise of 
      force (+dF/dt); rate of fall of force (-dF/dt); time to peak contraction (ttp); 
      duration of relaxation phase of contraction at the level of 10% of total 
      amplitude (tt10); and automatism (b.p.m.). Additionally, the influence of 
      thapsigargin on the effects of phenylephrine on the above mentioned parameters 
      were studied. It was found that TG (1 microM) decreased only the automatism in 
      rat heart, but increased automatism and ttp duration and decreased Fc in guinea 
      pig heart. The positive force-frequency relation in the guinea pig heart was 
      attenuated. The effects of phenylephrine in the rat heart were not significantly 
      different before and after pretreatment with TG. Alternatively, pretreatment with 
      TG exerted a profound influence on the effects of phenylephrine in the guinea pig 
      heart. The results indicate that TG has different effects on the guinea pig and 
      rat hearts. The reason for this could be due to species differences, i.e. the 
      weaker crossing of TG through the membrane of rat myocytes or a different 
      mechanism of Ca2+ homeostasis in rat and guinea pig hearts.
FAU - Kocic, I
AU  - Kocic I
AD  - Department of Pharmacology, Medical University of Gdansk, Poland.
FAU - Dworakowska, D
AU  - Dworakowska D
FAU - Dworakowski, R
AU  - Dworakowski R
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Pharmacol Res
JT  - Pharmacological research
JID - 8907422
RN  - 0 (Adrenergic alpha-Agonists)
RN  - 0 (Enzyme Inhibitors)
RN  - 1WS297W6MV (Phenylephrine)
RN  - 67526-95-8 (Thapsigargin)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
SB  - IM
MH  - Adrenergic alpha-Agonists/*pharmacology
MH  - Animals
MH  - Calcium-Transporting ATPases/antagonists & inhibitors/metabolism
MH  - Enzyme Inhibitors/*pharmacology
MH  - Female
MH  - Guinea Pigs
MH  - Heart/*drug effects/*physiology
MH  - Heart Rate/drug effects
MH  - In Vitro Techniques
MH  - Male
MH  - Myocardial Contraction/*drug effects
MH  - Myocardium/enzymology
MH  - Papillary Muscles/drug effects/physiology
MH  - Phenylephrine/*pharmacology
MH  - Rats
MH  - Rats, Wistar
MH  - Sarcoplasmic Reticulum/drug effects/enzymology
MH  - Thapsigargin/*pharmacology
EDAT- 1998/06/23 00:00
MHDA- 1998/06/23 00:01
CRDT- 1998/06/23 00:00
PHST- 1998/06/23 00:00 [pubmed]
PHST- 1998/06/23 00:01 [medline]
PHST- 1998/06/23 00:00 [entrez]
AID - S1043-6618(98)90299-7 [pii]
AID - 10.1006/phrs.1998.0299 [doi]
PST - ppublish
SO  - Pharmacol Res. 1998 Apr;37(4):273-80. doi: 10.1006/phrs.1998.0299.