Brainstem serotonergic neurons

The headquarters for the cell bodies of serotonergic neurons is in the brainstem area called the raphe nucleus (Fig. 5—51). Projections from the raphe to the frontal... 

FIGURE 5—56. Serotonergic neurons in brainstem sleep centers regulate sleep, especially slow-wave sleep. 

In the brain, serotonergic neurons are located in the brainstem in clusters of cells called the raphe nuclei, within which is the reticular network. These serotonergic neurons send their axonal projections throughout the entire brain. As a neurotransmitter, serotonin is involved in the regulation of numerous behavioral and physiological processes, including mood, appetite, sleep, sexual function, blood flow, body temperature, and more. The fact that both tryptophan and 5-HTP are chemical precursors for the synthesis of serotonin is presumably the reason for the claim of their efficacy in the treatment of problems related to mood, sleep, and appetite (Murray 1999). 

The serotonergic neurons of the raphe nuclei in the brainstem innervate the entire brain and likely exert substantial modulatory effects on our perceptions, emotions, thought processes, and conscious awareness— the mental states that may collectively be called the mind. Psilocybin and related tryptamines from Psilocybe fungi are believed to produce their profound effects on the brain and mind by way of interacting with 5-HT2A receptors in the cerebral cortex, limbic system, and elsewhere. As chemical probes that might lead to a better understanding of how the neural circuitry of the brain is related to the nature of mind, they offer unprecedented opportunities ... 

Guyenet PG, Stornetta RL, Riley T, Norton FR, Rosin DL, Lynch KR. a2A-Adrenergic receptors are present in lower brainstem catecholaminergic and serotonergic neurons innervating spinal cord. Brain Res 1994 638 285-294. 

Serotonergic neurons originate in the brainstem raphe nucleus and project widely throughout the entire CNS. Some of these projections are of particular relevance to an understanding of the antipanic effects of the SSRIs ... 

Serotonergic neuromodulatory system. The neurons that synthesize serotonin (molecular formula in hox) are located in a chain of midline brainstem neuronal clusters (called the raphe nuclei). They project caudally (to the spinal cord), locally (to the brainstem and cerebellum), and rostrally to the thalamus, subthalamus, limbic system, and cerebral cortex. Compare with figure 2.1 to identify structures shown. 

---