| Abstract: | We studied effects of forskolin, an activator of adenylate cyclase activity, and dioctanoyl-cyclic adenosine monophosphate (do-cAMP) on neutralizing (N) activity of concanavalin A (Con A). Biological testing was performed using explanted animal pole ectoderm of the Rana temporaria early gastrula. Con A treatment (200 micrograms/ml, 2 h) resulted in neutralization of 70-90% explants. If the explants were previously treated with forskolin (100 microM, 1 h), Con A effect decreased to 10%. When Con A and forskolin were applied simultaneously, no N-effect was observed. The same results were obtained with simultaneous treatment of the explants with Con A and do-cAMP (10(-5) M). Moreover, treatment with forskolin of the explants previously treated with Con A inhibited their neural differentiation. We suggest that N-effect of Con A is calcium dependent; the increase in intracellular cAMP after treatment of explants with forskolin or do-cAMP interferes with intracellular Ca2+ release and this results in the inhibited N-effect of Con A. |
