[Membrane signals: role of the inositol phosphate system]

Current information on cellular communications through plasmatic or synaptic mediators raises a great deal of questions about intracellular messengers diffusion and the apparent difference between the large number of intercellular mediators, or first messengers, and the few number of intracellular mediators, or second messengers. Regarding the intracellular messengers, the research is currently focused on the inositol phosphate system and especially on inositol-1,4,5 trisphosphate (IP3), which derives from the hydrolysis of a cellular membrane phosphoinositide: one of the most important function of IP3 is the release of intracellular calcium from the endoplasmic reticulum. The cell wall plays an important role in intracellular and intercellular communication as is shown by the balance between the cell-membrane phosphoinositide group and IP3 availability. Recent developments in knowledge about this inositol-phosphate system is going to show a new way of explanatory possibility about some not evident pathologies until now. The latest discovery of a specific intracellular receptor site of IP3 and the fact that some oligoelements, such as lithium, interfere with IP3 metabolism suggest exciting prospects for the treatment of pathologies resulting from these changes in receptor mechanism.