Phosphodiesterase in Tongue Epithelium: Activation by Bitter Taste Stimuli

Abstract

THE role of cyclic nucleotides in stimulus-response coupling at the cellular level has received much attention¹. The level of adenosine cyclic 3′,5′-monophosphate (cAMP) is dependent on its rate of synthesis, catalysed by adenyl cyclase, and on its rate of destruction, catalysed by phosphodiesterase. Although most investigators have measured the regulation of cAMP levels by alterations in adenyl cyclase activity, others have noted the presence of high levels of phosphodiesterase in certain sensory receptors and have suggested that this enzyme may be of special importance in such cells². We studied the phosphodiesterase activity in tongue epithelium to determine whether unusually high levels of this enzyme might also be associated with taste receptors, and to explore the possibility that taste stimuli might affect phosphodiesterase activity, thereby altering the intracellular cAMP concentrations.