Key result
Concanavalin A (5-200 micrograms/ml) induced a twofold to fivefold increase in the spontaneous beat rate of cultured aggregates of ventricular cells from seven-day chick embryos.
Concanavalin A increases the spontaneous beat rate of embryonic chick heart cell aggregates, suggesting a role for cell surface saccharide-bearing macromolecules in regulating beat rate.
Hypothesis-generating for saccharide roles in cardiac automaticity; leaves open any clinical relevance pending mammalian validation.
The plant lectin concanavalin A (Con A), at concentrations of 5-200 micrograms/ml, induced a twofold to fivefold increase in spontaneous beat rate of cultured aggregates of ventricular cells from seven-day chick embryos. This response was time, dose, and temperature dependent and was accompanied by a decrease in transmembrane potential. It could be blocked or reversed by alpha-methyl-D-mannoside but was not reversed by dilution alone. Binding of the lectin occurred in the cold, but a temperature-dependent process was also necessary to produce the response. Divalent (succinyl) Con A did not cause a beat rate increase. Whole heart aggregates responded similarly but less intensely than ventricular aggregates. Atrial aggregates, and whole heart aggregates treated with 5 microgram/ml of Con A, produced a biphasic chronotropic response, first decreasing then increasing their beat rates. These results suggest that saccharide-bearing macromolecules on the heart cell surface play a role in regulating spontaneous beat rate.
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Myrdal et al. (1983) studied Embryonic chick heart cell aggregates. Concanavalin A (Con A) was evaluated on Spontaneous beat rate. Concanavalin A (5-200 micrograms/ml) induced a twofold to fivefold increase in the spontaneous beat rate of cultured aggregates of ventricular cells from seven-day chick embryos.
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