Neurotransmitter interactions in the median raphe nucleus

The projections emanating from the serotonergic cell bodies located in the dorsal raphe nucleus and median raphe nucleus account for the majority of forebrain serotonin (5HT). Whereas the two projections of these nuclei are well documented their innervation and the neurotransmiters involved are not very well understood. Transmitters known to be present within the raphe nuclei include gamma-aminobutyric acid (GABA), norepinephrine, acetylcholine, substance P, and met-enkephalin. The adrenergic projections are known to come from the locus ceruleus (Loizou, 1969). The identification of the transmitter for the pathway projecting from the habenula to the raphe is less clear: both GABA and substance P have been proposed (Neckers et al., 1979, Wang, 1977). These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.