Mini-review: A possible role for galanin in post-traumatic stress disorder. (21st June 2021) - Ullrich, David
Highlights: Locus coeruleus derived galanin suppresses dopamine release into the mesolimbic and mesocortical pathways. Mesocorticolimbic dopamine is crucial in fear extinction processes and in modulating locus coeruleus reactivity. The locus coeruleus is dysregulated in patients with post-traumatic stress disorder, leading to excessive galanin release. Stimulation of the μ-opioid receptor counteracts the effects of galanin on mesocorticolimbic dopamine. Abstract: Several neuroendocrine systems have been implicated in post-traumatic stress disorder, including the mesocortical and mesolimbic dopamine, the norepinephrine, the β-endorphin, the serotonin, and the oxytocin systems. The interaction between these different systems remains, however, largely unknown and a generally accepted unifying theory is thus far lacking. In this review, we suggest that galanergic suppression of dopaminergic neurons in the ventral tegmental may constitute the missing link in a post-traumatic feedback loop. In addition, we address the literature on the negative cross-antagonism in this brain region between the galanin 1 and μ-opioid receptors, which suggests that behavioural patterns which stimulate β-endorphin, a natural μ-opioid receptors ligand, secretion may provide novel avenues for the treatment and prevention of PTSD, as well as for recruitment, training, and leadership processes in high-stress/high-risk professions such as the military, first responders and the police.