Phorbol 12-myristate 13-acetate modulates the cAMP-induced light-scattering response of a Dictyostelium discoïdeum cell population.
The effect of phorbol 12-myristate 13-acetate upon the light-scattering response to cAMP of a D. discoïdeum cell suspension was investigated. It was found that the first spike of the cAMP-mediated light-scattering change (peaking at about 15-20 s after stimulation) was inhibited by the phorbol ester. This effect was concentration dependent with an half-maximum value for the inhibition of 4 nM. The inhibition was found to be maximal after a 10-20 min incubation time. The phorbol ester was shown to affect the dose-response relationship between the cAMP concentration and the relative amplitude of the light-scattering change, more by decreasing the number of cAMP receptors than by decreasing their apparent affinity for cAMP.
Thiery
R
R
Institut Curie, Section de Physique et Chimie LPCB, URA 198 CNRS, Paris, France.
Klein
R
R
Tatischeff
I
I
D002633:Chemotaxis / Q000187:drug effects; D000242:Cyclic AMP / Q000494:pharmacology*; D004023:Dictyostelium / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008027:Light; D012542:Scattering, Radiation; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D000242:Cyclic AMP; D013755:Tetradecanoylphorbol Acetate