It is known that endogenous opioid receptors exist in the dorsal raphe nucleus, and that it is a focal point as an ascending and descending regulator.

Knowing that the spread of charge across such a short area is very plausible, as is an alternate connection to the raphe magnus, these results could be called into question.

A muscle relaxant, known as Mephenesin, reduces activity of the dorsal nucleus, as well as microinjections of carbachol (which induces atonia while awake).

Some studies have suggested that the dorsal raphe may be decreased in size in people with depression and, paradoxically, an increased cell density in those who die by suicide.

[7][8][9] An increased number of cells in the lateral aspects of the dorsal raphe is characteristic of primates (including humans).