Effect of pH on contractile state and transsarcolemmal Ca flux in cultured heart cells

Conference · Tue Mar 04 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6937029

Kim, D; Smith, T W

The mechanism of pH-induced changes in cardiac contractile state was investigated using spontaneously beating cultured chick embryo ventricular cells. Cells were equilibrated in HEPES-buffered medium at pH 7.4 and then exposed to pH 6.0, 7.4 or 8.8 medium. pH-induced changes in Ca uptake were insensitive to 1 ..mu..M verapamil but were sensitive to changes in Na gradient. pH 6.0 inhibited and pH 8.8 stimulated Na/sub i/-dependent Ca uptake. Replacement of Na in the efflux medium with choline during /sup 45/Ca efflux did not affect the pH-induced changes in Ca efflux, suggesting that pH alters Ca efflux via sarcolemmal Ca-ATPase. Intracellular alkalinization or acidification produced by NH/sub 4/Cl (20 mM) altered contractile state by +140% or -60%, respectively, but failed to alter significantly the /sup 45/Ca influx or efflux rates. The authors conclude that pH-induced alteration in contractile state is due in part to changes in transsarcolemmal Ca movement via Na/Ca exchange as well as sarcolemmal Ca pump activity. pH/sub i/-induced alteration in contractile state is due to changes in Ca movements within the cell and/or in Ca sensitivity of myofibrils.

• Research Organization: Harvard Medical School, Boston, MA
• OSTI ID: 6937029
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ALCOHOLS
ALKALI METALS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
AMINES
AMMONIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIRDS
BODY
CALCIUM
CALCIUM 45
CALCIUM ISOTOPES
CARDIOVASCULAR SYSTEM
CELL CULTURES
CHICKENS
CHOLINE
CONTRACTION
DAYS LIVING RADIOISOTOPES
DRUGS
ELEMENTS
EMBRYONIC CELLS
ENZYMES
EVEN-ODD NUCLEI
FOWL
HEART
HYDROLASES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LIPOTROPIC FACTORS
MEMBRANE TRANSPORT
METALS
NUCLEI
ORGANIC COMPOUNDS
ORGANS
PH VALUE
PHOSPHOHYDROLASES
QUATERNARY COMPOUNDS
RADIOISOTOPES
SODIUM
TRACER TECHNIQUES
VERTEBRATES