Urocortin 1 expression in five pairs of rat lines selectively bred for differences in alcohol drinking.
BACKGROUND
There is accumulating evidence that the neuropeptide urocortin 1 (Ucn1) is involved in alcohol consumption. Thus far, however, most studies have been performed in mice.


OBJECTIVE
The purpose of the present study was to characterize Ucn1 expression in rats selectively bred for either high or low alcohol intake.


METHODS
Brains from naive male rats of five pairs of independently selected lines (iP/iNP, AA/ANA, HARF/LARF, HAD1/LAD1, and HAD2/LAD2) were analyzed by immunohistochemistry.


RESULTS
Significant differences were found between iP/iNP, HARF/LARF, and HAD2/LAD2 in number of Ucn1-containing cells in the Edinger-Westphal (EW) nucleus (the main source of Ucn1 in the brain), whereas no significant differences were found between HAD1/LAD1 and AA/ANA. Similarly, significant differences in the optical density of Ucn1 immunoreactivity in EW were found between iP/iNP, HARF/LARF, and HAD2/LAD2, whereas no differences on this measure were found between HAD1/LAD1 and AA/ANA. In the lateral septum (LS, the main projection area of Ucn1-containing neurons in the rat), significant differences were found only between AA/ANA and HAD2/LAD2; however, a meta-analysis indicated that across all five lines, preferring animals had a significantly greater number of Ucn1-positive fibers than nonpreferring animals.


CONCLUSIONS
These results provide evidence that, in rats, Ucn1 may be involved in regulation of alcohol intake, and that this regulation may occur through the Ucn1 projections to LS.
Portland Alcohol Research Center, Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239, USA. turekv@ohsu.edu
V F
VF
Turek
N O
NO
Tsivkovskaia
P
P
Hyytia
S
S
Harding
A D
AD
Lê
A E
AE
Ryabinin
D000428:Alcohol Drinking / Q000235:genetics*; D000818:Animals; D001921:Brain / Q000378:metabolism; D001931:Brain Mapping; D003346:Corticotropin-Releasing Hormone / Q000235:genetics*; D015870:Gene Expression; D009415:Nerve Net / Q000378:metabolism; D010641:Phenotype; D051381:Rats; D011919:Rats, Inbred Strains; D012641:Selection, Genetic; D012688:Septum Pellucidum / Q000378:metabolism; D054832:Urocortins
D054832:Urocortins; D003346:Corticotropin-Releasing Hormone