ABSTRACT
Synaptic interactions in the brainstem are based upon two basic characteristics of functional organization. On the one hand, neurons with different functional correlates overlap anatomically and interact functionally in most anatomical subdivisions of the brainstem and, on the other hand, brainstem functions require relationship between different cell groups with distinct anatomical locations. Data are available on the immunochemistry and in situ hybridization of neurotransmitters with potential biological roles in the nucleus tractus solitarii (NTS). Sensory afferents to the NTS exhibit periodic discharges of spike trains related to ventilatory or cardiac cycles, while in NTS neurons, a combination of potassium currents with high- and low-threshold calcium currents produces beating patterns comprised of a discharge of single action potentials at low frequency. Evidence for peptidergic modulation of NTS glutamatergic or gama aminobutyric acid-ergic transmission has been reported using opioids, neurotensin, cholecystokinin, Serotonin-3, metabotropic glutamate, and γ-aminobutyric acidB agonists.
