Figure 2
From: Transcriptional dysregulation of 5-HT1A autoreceptors in mental illness
5-HT1A autoreceptor-mediated negative feedback on 5-HT neurons. A model of a serotonergic neuron (5-HT neuron) projecting to a target neuron (postsynaptic neuron) is shown, with 5-HT1A receptors depicted as yellow ovals, and other 5-HT receptors as other colored ovals. Acutely, SSRI's rapidly enter the brain and block 5-HT transporters (green diamonds), located at the raphe serotonin nerve terminal, but also at the cell body and dendrites in the raphe nuclei. This block of reuptake leads to accumulation of extracellular 5-HT (red dots) at both sites once released by depolarization. Activation of 5-HT1A autoreceptors located at the cell body and dendrites leads to inhibition of neuronal firing rate (red action potential), thus compensating for increase in 5-HT induced by SSRI treatment, resulting in little change in 5-HT neurotransmission initially.