Concanavalin A increases spontaneous beat rate of embryonic chick heart cell aggregates
✍ Scribed by Sigrid E. Myrdal; Robert L. Dehaan
- Publisher
- John Wiley and Sons
- Year
- 1983
- Tongue
- English
- Weight
- 739 KB
- Volume
- 117
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
The plant lectin concanavalin A (Con A), at concentrations of 5-200 pg/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 amethyl-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 pg/ml of Con A, produced a biphasic chronotropic response, first decreasing then increasing their beat rates. These results suggest that saccharide-bearing macromolecules on t h e heart cell surface play a role in regulating spontaneous beat rate.