Molecular examination of the endogenous opioid system in rhesus macaque monkeys with self‐injurious behavior. Issue 1 (22nd September 2022)

• Record Type: Journal Article
• Authors: Jackson, Marques; Foret, Brittany L.; Fontenot, Jane; Hasselschwert, Dana; Smith, Josh; Romero, Emily; Smith, Karen Müller
• Is Part Of: Journal of neuroscience research. Volume 101:Issue 1(2023)
• Page Start: 70
• Page End: 85
• Publication Date: 2022-09-22
• Subjects: β endorphin -- μ opioid receptor -- dynorphin -- NSSI -- POMC -- prodynorphin -- RRID:SCR_008279 -- RRID:SCR_008406 -- RRID:SCR_014242 -- RRID:SCR_014281 -- RRID:SCR_0158040 -- RRID:SCR_015805 -- RRID:SCR_016137 -- self‐harm -- SIB; Neurobiology -- Periodicals; 612
• DOI: 10.1002/jnr.25128
• Languages: English
• ISSNs: 0360-4012

Abstract

Abstract: Self‐injurious behavior (SIB) can lead to serious injury and occurs in approximately 1%–4% of the adult population, with higher incidences in adolescent and institutionalized populations, as well as in children with developmental disorders such as Autism. SIB also spontaneously occurs in a low percentage of captive monkeys. Rhesus macaque ( Macaca mulatta ) monkeys are evolutionarily and physiologically similar to humans, share 93% genetic sequence similarity to humans, and have long been used as testing subjects for vaccine and clinical trials. Previous studies hypothesized that altered endogenous opioid expression occurs in the brains of individuals and animals that self‐injure. We examined the regional mRNA expression of opioid signaling genes in sixteen rhesus macaques that exhibited SIB and eight sex‐ and age‐ matched controls. The brain regions examined are linked to reward reinforcement and stress adaptation including the hypothalamus, orbital frontal cortex, nucleus accumbens, hippocampus, caudate, and the amygdala. We found decreased μ‐opioid receptor ( OPRM1 ) in the amygdala of monkeys with SIB, and reduced prodynorphin ( PDYN ) in the hypothalamus. Our data suggest dysfunction in the regulation of opioid peptide precursors and calls for further investigation of the endogenous opioid system in SIB. Abstract : The expression of genes related to endogenous opioid signaling was examined in Rhesus macaque ( Macaca mulatta ) monkeys that self‐injure compared to control monkeys, in brain regions important for behavioral and emotional regulation including the amygdala, orbitofrontal cortex, caudate, nucleus accumbens, hippocampus, and hypothalamus. Reduced mRNA levels for the mu opioid receptor were measured in the amygdala, while reduced mRNA levels of dynorphin mRNA were observed in the hypothalamus in monkeys that self‐injure compared to controls. This study confirms and extends our knowledge of endogenous opioid signaling in self‐injurious behaviors.