serotonin signaling pathway serotonin signaling pathway via receptors engaging G alphas protein family 2012-08-01T03:28:58Z PW:0001091 SMP:00309 SMP:00311 SMP:00312 Serotonin signaling via receptor family 4, 6, and 7 engages G alphas protein family resulting in activation of adenylyl cyclases and increased concentration of cAMP. There are seven receptor subtypes in family 4 and only one in families 6 and 7. pathway vpetri