Gene expression of opioid and dopamine systems in mouse striatum: effects of CB1 receptors, age and sex

Abstract

Rationale-Endocannabinoid, opioid, and dopamine systems interact to exhibit cannabinoid receptor neuromodulation of opioid peptides and D 4 dopamine receptor gene expression in CB 1 -cannabinoid-deficient mouse striatum.Objective-Using CB 1 -transgenic mice, we examine primary age-sex influences and interactions on opioid and dopamine system members' gene expression in striatum. Results-(1) Increased PPENK and PPDYN, owing to genotype [CB 1 (+/+) vs. CB 1 (−/−)], depended on sex. When genotype-independent, they depended on sex (PPENK) or age (PPDYN).(2) δ-OR was age-dependent (higher in old). (3) μ-OR, owing to genotype, was age-dependent [higher in old CB 1 (−/−) males]. When genotype-independent, it depended on sex (higher in NIH Public Access Author ManuscriptPsychopharmacology (Berl). Author manuscript; available in PMC 2013 July 11.

Sex differences in affective response to opioid withdrawal during adolescence

“…Additionally, females were suggested to express lower levels of the mu opioid receptors in the ventral periaqueductal gray (Bernal et al, 2007). Sex differences were also observed in expression levels of preproenkephalins, where female mice had higher expression levels in the striatum as compared with males (Gerald et al, 2008). Unfortunately, there is limited literature examining sex differences in the expression of different components of the opioid system, especially in those key brain areas suggested to be involved in the modulation of FST behaviors.…”

Exposure to opiates in female adolescents alters mu opiate receptor expression and increases the rewarding effects of morphine in future offspring

“…There is a growing literature indicating sex-specific expression patterns of opioid receptors as well as endogenous opioid expression, particularly in relation to the differential antinociception response between males and females (Gerald et al, 2008; Kren et al, 2008; Meyer et al, 2000; Wang et al, 2012). For example, it has been shown that there are sex-specific increases in mu opioid receptor expression within the spinal cord in male but not female rats (Verzillo et al, 2014) and the periaqueductal gray region (Loyd et al, 2008).…”

Sex differences in the neural mechanisms mediating addiction: a new synthesis and hypothesis

“…A summary of the published information about sex differences in the neurochemistry of the reward system appears in this figure [193,225,226,228,269,329,330,332,353,354,356,370,384,392,423,430,434,435,480-521]. Abbreviations are as follows, (R): data collected from rodents; (H) data collected from humans M: male, F: female, for other abbreviations see list.…”

“…These sex differences are not always apparent [355,356], which may reflect the changes in the concentrations of these peptides over the course of the estrous cycle [357]. DYN peptide levels are relatively stable across the cycle in the NAc, whereas there is a significant reduction in the DS during estrus.…”