2003, Samuel H. Barondes, chapter 4, in Better than Prozac, Oxford University Press, →ISBN, page 54:
Its action as an inhibitor also distinguishes GABA from the “big three” amines—dopamine, norepinephrine, and serotonin—which generally stimulate brain circuits.
2005 December, Smith, D.C. et al., “Electrical stimulation of the vagus nerve enhances cognitive and motor recovery following moderate fluid percussion injury in the rat”, in Journal of Neurotrauma[1], →DOI:
Recent evidence suggests that some of these effects of VNS may be due to the activation of neurons in the nucleus locus coeruleus resulting in the release of norepinephrine (NE) throughout the neuraxis. Because antagonism of NE systems has been shown to delay recovery of function following brain damage, it is possible that enhanced release of NE in the CNS may facilitate recovery of function.
