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Content of Dynorphins and k‐Opioid Receptors in Distinct Brain Regions of C57BL/6 and DBA/2 Mice
Author(s) -
Jamensky Neil T.,
Gianoulakis Christina
Publication year - 1997
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.1997.tb04476.x
Subject(s) - dynorphin , nucleus accumbens , κ opioid receptor , chemistry , endocrinology , medicine , opioid peptide , ventral tegmental area , opioid , dynorphin a , receptor , endogenous opioid , dopamine , biology , biochemistry , dopaminergic
Differences in the activity of various components of the endogenous opioid system under basal conditions and after ethanol exposure have been reported between strains and lines of animals showing either high or low ethanol consumption. The objective of the present studies was to investigate the presence of differences in (a) the density of k‐opioid binding sites, (b) the content of prodynorphin mRNA, and (c) the content of dynorphin peptides in distinct brain regions between the C57BL/6 (ethanol‐preferring) and the DBA/2 (ethanol‐avoiding) mice. Results indicated that the C57BL/6 mice have a higher content of k‐opioid binding sites and dynorphin A1‐13 in the amygdala, and dynorphin A 1–8 in the ventral tegmental area, whereas the DBA/2 mice presented a significantly higher content of k‐opioid binding sites, prodynorphin mRNA, as well as dynorphin A 1–13 and dynorphin A 1–8 peptides in the nucleus accumbens and septum. In addition, the DBA/2 mice presented a higher content of k‐opioid receptors in the periaqueductal gray and dynorphin A1‐13 and dynorphin A 1–8 in the caudate putamen. Because enhanced stimulation of the k‐opioid receptors at the level of the nucleus accumbens has been associated with decreased dopamine release and aversive states, the higher content of k‐opioid receptors, prodynorphin mRNA, and dynorphin peptides (the endogenous ligand of k‐binding sites) in regions of the limbic system of the DBA/2 mice may play an important role in determining their low alcohol consumption.