Molecular Neurobiology. Description Choose one of the questions below 1. “Alterations in Serotonin reuptake transporters (SERT) and specific serotonin receptors play a critical role in the aetiology of affective disorders”. With a focus on SERTs and/or serotonin receptors consider to what extent this statement is true. 2. Critically consider the degree to which endogenous opioids and/or their receptors are involved in pleasure responses