Pharmacology of the neurotransmission of the baro- and chemoreflex in the Nucleus Tractus Solitarius

The Nucleus Tractus Solitarius (NTS) is located in the dorsal aspect of the brainstem and is the central station for visceral afferents (baro- and chemoreflexes) where these inputs are processed and integrated in order to modulate autonomic and respiratory function. A complex network of cells controls the fine synaptic activity of the baro- and chemoreflex within the NTS, including excitatory neuronal afferents, inhibitory interneurons, and astrocytes. l-glutamate and GABA are the major neurotransmitters modulating the activity of NTS neurons. However, other neuromodulators, such as ATP, adenosine, and NO, also play a role under different physiological challenges. In this chapter, our focus is the current knowledge about the role of glutamatergic and GABAergic signaling in the NTS, their respective receptors, and neurotransmitter transporters located on astrocytes, in the modulation of autonomic and respiratory responses to baro- and chemoreflex activation.