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


METHODS
Real-time quantitative polymerase chain reaction was used to analyze gene expression of opioid peptides [preproenkephalin (PPENK); preprodynorphin (PPDYN)], opioid receptors [delta-opioid receptor (delta-OR); mu-opioid receptor (micro-OR)] and dopamine receptor subtypes (D(1) through D(5)) in male/female CB(1)(+/+)/CB(1)(-/-) mice striata at two adult ages [young (60-90 days); old (140-300 days)].


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) delta-OR was age-dependent (higher in old). (3) micro-OR, owing to genotype, was age-dependent [higher in old CB(1)(-/-) males]. When genotype-independent, it depended on sex (higher in females). (4) Female D(1) was genotype-independent and age-dependent, while male D(1) was higher in old over young CB(1)(+/+) mice. (5) D(5), owing to genotype, was sex-dependent [higher in young female CB(1)(-/-) mice]. (6) D(2), genotype-independent, was higher in old over young male mice. (7) Young female D(3) was higher in CB(1)(-/-) over CB(1)(+/+) mice. Male D(3) was age-dependent (higher in old mice). (8) D(4), owing to genotype, was sex-dependent [higher in CB(1)(-/-) over CB(1)(+/+) females]. Genotype-independent D(4) was sex-dependent in young mice (higher in females) and age-dependent in males (higher in old).


CONCLUSIONS
Greater striatal expression is genotype-dependent in females (opioid-peptides, D(3), D(4), D(5)) and genotype-independent in both females (PPENK, mu-OR, D(4)) and old males (PPDYN, delta-OR, D(2), D(3), D(4)).
Gerald
Tonya M
TM
Chemistry Department, North Carolina Central University, Durham, NC 27707, USA.
Howlett
Allyn C
AC
Ward
Gregg R
GR
Ho
Cheryl
C
Franklin
Steven O
SO
D000375:Aging / Q000378:metabolism*; D000818:Animals; D005260:Female; D015870:Gene Expression / Q000502:physiology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D017072:Neostriatum / Q000378:metabolism*; D018847:Opioid Peptides / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D043884:Receptor, Cannabinoid, CB1 / Q000235:genetics* / Q000502:physiology*; D011954:Receptors, Dopamine / Q000235:genetics*; D017447:Receptors, Dopamine D1 / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000235:genetics; D050637:Receptors, Dopamine D3 / Q000235:genetics; D050638:Receptors, Dopamine D4 / Q000235:genetics; D050641:Receptors, Dopamine D5 / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000502:physiology; D011957:Receptors, Opioid / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012727:Sex Characteristics
D018847:Opioid Peptides; D012333:RNA, Messenger; D043884:Receptor, Cannabinoid, CB1; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D043562:Receptors, G-Protein-Coupled; D011957:Receptors, Opioid; D050638:Receptors, Dopamine D4; D050641:Receptors, Dopamine D5