Two other neurotransmitters, orexin and gamma-Aminobutyric acid (GABA), seem to promote wakefulness, diminish during deep sleep, and inhibit paradoxical sleep.
two otHeR NeuroTransmItteRs, OReXin and GamMA-AminobuTYrIc acid (gaba), seeM to promOTe wakefulnEss, DimINish during deeP sLeeP, and iNhIbIt parAdoxiCal slEEp.