Guinea-pig Heart Cells Research Articles

Possible role of slow sodium-calcium channels in the mechanism of changes in electrical and mechanical activity of guinea pig heart cells in local anaphylaxis (the isoptine effects).

The local anaphylactic reaction and the effects of histamine during blocking of the slow sodium-calcium channels by isoptine were investigated in the spontaneously contracting oracle of the atrium of a guinea pig previously sensitized to egg albumin. Simultaneously with the intracellular recording of the potentials, isometric contractions of the preparation were recorded by means of a mechanotron. The investigation showed that egg albumin (0.2 mg/ml) and histamine (0.1 mg/ml) are antagonists of isoptine (2-16 mg/liter) as regards its effect on automatic contraction and duration of the action potential. It is postulated that this anaphylatic reaction is based on activation of the slow sodium-calcium channels in the surface membrane of the myocardial fibers.

Nuclear pores in ventricular muscle cells from adult hypertrophied hearts

Nuclear pores were observed in myocardial cells in both spontaneous and experimentally induced hypertrophy. The ultrastructure of these pores was studied in cross sections and tangential sections of hypertrophied rabbit, hamster and guinea pig heart cells. The morphology was similar to that previously seen in normal cardiac cells and in other cell types. Clusters of nuclear pores were frequently seen, and the closest center-to-center spacing between pores was 1400 Å. Annular granules with associated fibrils were observed on both the cytoplasmic and nucleoplasmic sides of the nuclear envelope. Many of the pores contained granules ∼ 300 Å in diameter which sometimes appeared hollow. The presence of large numbers of nuclear pores in hypertrophied cardiac cells supports the hypothesis that transport of material necessary for RNA-mediated protein synthesis may occur through the pores. Furthermore the mature cardiocyte provides an opportunity to study nuclear pore function in nuclei that do not synthesize DNA or divide.

Studies on the mode of action of diphtheria toxin. II. Protein synthesis in primary heart cell cultures.

Primary heart cell cultures of embryonic guinea pigs and the neonatal rat were established and incubated with purified diphtheria toxin. The rat heart cell cultures were refractory to the effects of the toxin; protein synthesis proceeded normally as measured by the incorporation of tritiated leucine into cell proteins; beating heart cells continued to contract; and the cell monolayers remained intact after exposure to the toxin for periods as long as 72 hr. These findings are compatible with the species resistance of the rat to diphtheria toxin. The guinea pig heart cell cultures were found to be extremely sensitive to the toxin. Protein synthesis was inhibited by approximately 50% after incubation with small quantities of toxin for 3 hr. Increasing the concentration of the length of exposure to the toxin did not increase this inhibition significantly. In addition, diphtheria toxin exerted a true cytopathic effect on the guinea pig heart cells. Monolayers were destroyed when incubated with the toxin for 2 to 3 days. The results show that the heart cells reflect species resistance or sensitivity to diphtheria toxin in the absence of neural or endocrine influences and suggest further that the toxin exerts a direct toxicity to muscle cells of the heart. It is not yet possible to explain in biochemical terms why the toxin seems to act specifically on cardiac tissues.

Cytopathic effect of mumps and other viruses in guinea pig heart cells.

Cytopathic effect of mumps and other viruses in guinea pig heart cells.

Cytopathic effect of mumps and other viruses in guinea pig heart cells.

Cytopathic effect of mumps and other viruses in guinea pig heart cells.

Demonstration of Venezuelan equine encephalomyelitis in tissue culture by immunofluorescence.

SummaryIn a guinea pig heart cell line, infected with an egg-adapted strain of Trinidad VEE, the virus could be demonstrated by immunofluorescence prior to development of CPE. Formalin fixation preserved the antigenicity, and the cover slips could be stored in this fixative at 4°C for periods up to 2 weeks without diminution of specific fluorescence. A whole burro serum conjugated with fluorescein isothiocyanate with a counterstain added proved a more reliable reagent than fractionated or absorbed sera. The model as described has the possibility of obtaining a specific viral diagnosis at the clinical level in the period normally required for initial isolation by conventional cell culture technics.