Agent Action
Fluoride activates Gs Cholera toxin inhibits GTPase activity of Gs Forskolin activates adenyl cyclase Pertussis toxin inhibits Gi Methylxanthines (theophylline, caffeine) inhibit phosphodiesterase Phorbol esters activate protein kinase C Calcium ionophores increase membrane permeability to calcium Calcium chelators (ethylenediaminetetraacetate) bind/inactivate calcium