Effect of phorbol esters on contractile state and calcium flux in cultured chick heart cells
Phorbol esters are potent tumor promoters that have been widely used in studies of transmembrane signaling because of their ability to activate protein kinase C. To study the effect of phorbol esters (and indirectly, the role of protein kinase C) on the cardiac muscle contractility, the authors examined the effects of phorbol myristate acetate (PMA) on contractile state, transmembrane /sup 45/Ca fluxes, and cytosolic free Ca concentration ((Ca)/sub i/) using spontaneously contracting cultured chick ventricular cells. PMA produced a concentration- and time-dependent decrease in the amplitude of cell motion (half maximum inhibitory concentration) with maximal effect observed at 1 ..mu..M. PMA (1 ..mu..M) reduced /sup 45/Ca uptake rate by 16 /plus minus/ 4% and the size of the rapidly exchangeable Ca pool by 11 /plus minus/ 2%, but did not alter the /sup 45/Ca efflux rate. In fura-2-loaded cells. PMA produced a decrease in (Ca)/sub i/ from 96 /plus minus/ 7 to 72 /plus minus/ 5 nM with a time course similar to that of alteration in contractile amplitude. These results indicate that PMA influences transsarcolemmal Ca uptake, and thus the excitation-contraction process, and suggest that protein kinase C may modulate myocardial Ca homeostassis and contractile state.
- Research Organization:
- Brigham and Women's Hospital, Boston, MA (USA)
- OSTI ID:
- 6395562
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 253:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Phorbol ester stimulates calcium sequestration in saponized human platelets
The effect of the PKC inhibitor calphostin C and the PKC agonist phorbol 12-myristate 13-acetate on regulation of cytosolic Ca{sup 2+} in mammalian skeletal muscle cells
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CALCIUM 45
MEMBRANE TRANSPORT
PHORBOL ESTERS
BIOLOGICAL EFFECTS
CALCIUM COMPOUNDS
CATIONS
CELL CULTURES
CHICKENS
DOSE-RESPONSE RELATIONSHIPS
HEART
MUSCLES
PHOSPHOTRANSFERASES
SODIUM COMPOUNDS
TIME DEPENDENCE
TUMOR PROMOTERS
ALKALI METAL COMPOUNDS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIRDS
BODY
CALCIUM ISOTOPES
CARCINOGENS
CARDIOVASCULAR SYSTEM
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
ENZYMES
ESTERS
EVEN-ODD NUCLEI
FOWL
INTERMEDIATE MASS NUCLEI
IONS
ISOTOPES
NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHOSPHORUS-GROUP TRANSFERASES
PROMOTERS
RADIOISOTOPES
TRANSFERASES
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology
550201 - Biochemistry- Tracer Techniques