Microfilaments and cellular signal transduction: effect of cytochalasin D on the production of cAMP, inositol phosphates, and on calcium movements in rat parotid glands.

In rat parotid glands, the involvement of the microfilament system in the cellular signal transmission mechanism was tested by measuring the effect of cytochalasin D (which disturbs the microfilament system) on the production of intracellular second messengers. Cytochalasin D (CD) did not affect unstimulated calcium movements (measured by the 45Ca efflux technique) or inositol phosphate production or cAMP accumulation. Neither did it modify the generation of intracellular second messengers induced by activation of the cholinergic muscarinic receptor (calcium and inositol phosphates). CD dit not affect the cAMP accumulation induced by the activation of the beta-adrenergic receptor whereas it strongly inhibited the calcium movements induced by activation of the same receptor. These data suggest that, in rat parotid glands, calcium movements, induced by beta-adrenergic receptor stimulation need an intact microfilament system to occur, whereas the muscarinic pathway (via IP3) does not.