Studies of Intracellular pH Regulation in Cardiac Myocytes From the Marine Bivalve Mollusk, <i>Mercenaria campechiensis</i>

Ellington, W. Ross

doi:10.2307/1542228

Cited by 17 publications

(8 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Average values of b NB,NPi varied between 28.5 mmol pH )1 kg )1 and 36.7 mmol pH )1 kg )1 wet weight in the Littorina spp. studied and were in the low range reported for other invertebrate and lower vertebrate species, possibly for methodological reasons (Eberlee and Storey 1984;Heisler 1986;Wiseman and Ellington 1989;Zange et al 1990;Ellington 1993;PoÈ rtner 1990;PoÈ rtner at al. 1996;van Dijk et al 1997).…”

Section: Discussionmentioning

confidence: 77%

Resistance to freshwater exposure in White Sea Littorina spp. II: Acid-base regulation

Sokolova

Bock

Pörtner

2000

Journal of Comparative Physiology B: Biochemical, Systemic, and

View full text Add to dashboard Cite

Parameters of acid-base and energy status were studied by in vivo 31 P-nuclear magnetic resonance spectroscopy in three White Sea Littorina spp. (L. littorea, L. saxatilis and L. obtusata) during prolonged anaerobiosis in freshwater. Intracellular pH decreased signi®cantly, especially during the early period of anaerobiosis, but later the decrease in intracellular pH slowed down considerably, suggesting a capacity for intracellular pH regulation in all three species. There was a trend for intracellular pH to fall most rapidly in the least freshwater-resistant species, L. obtusata, as compared to the most resistant, L. littorea. Non-bicarbonate, non-phosphate bu er values estimated by the homogenate technique were similar in the three studied species (28±37 mmol pH )1 kg )1 wet weight) and did not change during freshwater exposure. The CaCO 3 bu er value of the foot tissues was considerably higher (171± 218 mmol pH )1 kg )1 wet weight) and decreased signi®-cantly during freshwater exposure. The contribution of the multiple tissue bu ering systems to intracellular pH regulation in Littorina spp. shifts between di erent stages of freshwater exposure. Initially, the non-bicarbonate, non-phosphate tissue bu ering system seems to be of major importance for metabolic proton bu ering at intracellular pH between 7.5 and 7.0. During later stages of anaerobiosis and at lower intracellular pH, the CaCO 3 bu er is involved in proton bu ering. Decrease in the CaCO 3 bu er value during freshwater exposure was in quantitative agreement with the amount of metabolic protons bu ered, thus suggesting that CaCO 3 tissue stores may serve as a major bu ering system during prolonged anaerobiosis in Littorina spp.

show abstract

Section: Discussionmentioning

confidence: 77%

Resistance to freshwater exposure in White Sea Littorina spp. II: Acid-base regulation

Sokolova

Bock

Pörtner

2000

Journal of Comparative Physiology B: Biochemical, Systemic, and

View full text Add to dashboard Cite

show abstract

“…In the literature; data obtained using patch clamp and/ or immunostaining, ultrastructural studies concerned cultured cardiomyocytes from scallop, oyster and mussel (Wen et al 1993a;Le Deuff et al 1994;Curtis et al 1999;Le Marrec-Croq et al 1999;Pennec et al 2002Pennec et al , 2004Droguet 2006). Chen and Wen (1999) for oyster and Ellington (1993) for clam concluded that cultured fibroblastic cells were cardiomyocytes only by distinctive rhythmic contraction in vitro. In the present work proof that almost all adherent fibroblastic cells were cardiomyocytes was based on (1) the spontaneous beatings of fibroblastic cells observed in vitro with a rate similar to this measured in vivo, (2) results of immunological staining, showing positive reaction of these cells after treatment with antibodies against troponin, tropomyosin, myosin and sarcomeric actinin, (3) their ultrastructural characteristics and (4) results of electrophysiological analyses showing ionic channels and regulatory mechanisms very similar to those observed in cardiomyocytes of invertebrates and other marine bivalves (Pennec et al 2004;Curtis et al 1999).…”

Section: Discussionmentioning

confidence: 99%

Establishment of functional primary cultures of heart cells from the clam Ruditapes decussatus

Hanana¹,

Talarmin²,

Pennec³

et al. 2011

Cytotechnology

View full text Add to dashboard Cite

Heart cells from the clam Ruditapes decussatus were routinely cultured with a high level of reproducibility in sea water based medium. Three cell types attached to the plastic after 2 days and could be maintained in vitro for at least 1 month: epithelial-like cells, round cells and fibroblastic cells. Fibroblastic cells were identified as functional cardiomyocytes due to their spontaneous beating, their ultrastructural characteristics and their reactivity with antibodies against sarcomeric a-actinin, sarcomeric tropomyosin, myosin and troponin T-C. Patch clamp measurements allowed the identification of ionic currents characteristic of cardiomyocytes: a delayed potassium current (I K slow ) strongly suppressed (95%) by tetraethylammonium (1 mM), a fast inactivating potassium current (I K fast ) inhibited (50%) by 4 amino-pyridine at 1 mM and, at a lower level (34%) by TEA, a calcium dependent potassium current (I KCa ) activated by strong depolarization. Three inward voltage activated currents were also characterized in some cardiomyocytes: L-type calcium current (I Ca ) inhibited by verapamil at 5 9 10 -4 M, T-type Ca 2? current, rapidly activated and inactivated, and sodium current (I Na ) observed in only a few cells after strong hyperpolarization. These two currents did not seem to be physiologically essential in the initiation of the beatings of cardiomyocytes. Potassium currents were partially inhibited by tributyltin (TBT) (1 lM) but not by okadaic acid (two marine pollutants). DNA synthesis was also demonstrated in few cultured cells using BrdU (bromo-2 0 -deoxyuridine). Observed effects of okadaic acid and TBT demonstrated that cultured heart cells from clam Ruditapes decussatus can be used as an experimental model in marine toxicology.

show abstract

“…Maintaining pH e regulation is important to maintain oxygen supply to the tissues [ 73 , 74 ] and for acid-base equilibrium within the limits needed for protein/enzyme function; however, a range of pH e has been noted in crustaceans under different environmental scenarios [ 30 , 42 , 68 , 69 , 75 ]. Unlike pH e , the pH i is tightly controlled in most marine animals despite changes to the pH e [ 75 – 77 ]. A crustaceans metabolism, protein synthesis, ion-regulation, and cell volume are effected by even small changes in the pH i [ 75 , 78 – 80 ].…”

Section: Discussionmentioning

confidence: 99%

Ocean Acidification Affects Hemocyte Physiology in the Tanner Crab (Chionoecetes bairdi)

et al. 2016

View full text Add to dashboard Cite

We used flow cytometry to determine if there would be a difference in hematology, selected immune functions, and hemocyte pH (pHi), under two different, future ocean acidification scenarios (pH = 7.50, 7.80) compared to current conditions (pH = 8.09) for Chionoecetes bairdi, Tanner crab. Hemocytes were analyzed after adult Tanner crabs were held for two years under continuous exposure to acidified ocean water. Total counts of hemocytes did not vary among control and experimental treatments; however, there were significantly greater number of dead, circulating hemocytes in crabs held at the lowest pH treatment. Phagocytosis of fluorescent microbeads by hemocytes was greatest at the lowest pH treatment. These results suggest that hemocytes were dying, likely by apoptosis, at a rate faster than upregulated phagocytosis was able to remove moribund cells from circulation at the lowest pH. Crab hemolymph pH (pHe) averaged 8.09 and did not vary among pH treatments. There was no significant difference in internal pH (pHi) within hyalinocytes among pH treatments and the mean pHi (7.26) was lower than the mean pHe. In contrast, there were significant differences among treatments in pHi of the semi-granular+granular cells. Control crabs had the highest mean semi-granular+granular pHi compared to the lowest pH treatment. As physiological hemocyte functions changed from ambient conditions, interactions with the number of eggs in the second clutch, percentage of viable eggs, and calcium concentration in the adult crab shell was observed. This suggested that the energetic costs of responding to ocean acidification and maintaining defense mechanisms in Tanner crab may divert energy from other physiological processes, such as reproduction.

show abstract

Studies of Intracellular pH Regulation in Cardiac Myocytes From the Marine Bivalve Mollusk, Mercenaria campechiensis

Cited by 17 publications

References 30 publications

Resistance to freshwater exposure in White Sea Littorina spp. II: Acid-base regulation

Resistance to freshwater exposure in White Sea Littorina spp. II: Acid-base regulation

Establishment of functional primary cultures of heart cells from the clam Ruditapes decussatus

Ocean Acidification Affects Hemocyte Physiology in the Tanner Crab (Chionoecetes bairdi)

Contact Info

Product

Resources

About