Causal and functional interpretation of mu- and delta-opioid receptor profiles in mesoaccumbens and nigrostriatal pathways of an oral stereotypy phenotype.

Causal and functional interpretation of mu- and delta-opioid receptor profiles in mesoaccumbens and nigrostriatal pathways of an oral stereotypy phenotype.
Behav Brain Res. 2018 Jun 28;:
Authors: Hemmings A, Parker MO, Hale C, McBride SD
Abstract
Spontaneous stereotypic behaviours are repetitive, compulsive, topographically invariant response patterns commonly observed in captive or domestic animals, which have been linked to dysfunction of basal ganglia input/output pathways. There is evidence that endogenous opioids play a key regulatory role in basal ganglia direct and indirect pathways, but their precise role, both causally and functionally, in spontaneous stereotypic behaviour is unclear. Here we examined the profile of mu- and delta-opioid receptors (density [Bmax] and affinity [Kd]) of basal ganglia structures in stereotypy (n = 10) and non-stereotypy (n = 10) animals using a competitive ligand binding approach. Mu receptor densities were significantly higher in the nucleus accumbens (p < 0.001), ventral tegmentum area (p < 0.001) and caudate nuclei (p < 0.001) of stereotypy compared to control animals. No differences were observed for delta Bmax values in any of the brain regions studied (p > 0.15). Receptor binding affinity were only found to be significantly different between control and stereotypy animals for mu receptors on the caudate region; (p < 0.001). Our findings suggest th...

Source: Behavioural Brain Research - June 28, 2018 Category: Neurology Authors: Hemmings A, Parker MO, Hale C, McBride SD Tags: Behav Brain Res Source Type: research