5-HT2 receptors signaling. Main pathways of intracellular signaling for these serotonine receptors subtype involve rupture of membrane phospholipids, particularly with phospholipase C (PLC) producing diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3) from phosphatidylinositol 4,5-bisphosphate (PIP2). These second messengers activate protein kinase C (PKC) which in time may activate the extracellular signal-regulated kinases 1 and 2 (ERK1/2) [50]. Phospholipase A2 is eventually activated producing arachidonic acid (AA) from phosphatidylcholine (PC), or phosphatidic acid (PA) by means of phospholipase D (PLD) [44, 50]. SERT is included in the diagram, coexisting in astrocytes for example, to emphasize the intracellular participation of serotonin itself [14]. Other pathways including (Rho-GEF) and (PI3K) are shown [51]. MEK, mitogen-activated protein kinase; PH, phosphohydrolase enzyme; PKA, protein kinase A-relation to cAMP pathways; SERT, serotonin transporter.
