The Journal of Neuroscience, March 15, 2003, 23(6):2477
The Edinger-Westphal-Lateral Septum Urocortin Pathway and Its
Relationship to Alcohol Consumption
Ryan K.
Bachtell1,
Adam
Z.
Weitemier1,
Agustin
Galvan-Rosas1,
Natalia O.
Tsivkovskaia1,
Fred O.
Risinger1,
Tamara J.
Phillips1, 2,
Nicholas J.
Grahame3, and
Andrey E.
Ryabinin1
1 Department of Behavioral Neuroscience, Oregon Health
and Science University and Portland Alcohol Research Center, Portland,
Oregon 97239, 2 Department of Veterans Affairs Medical
Center, Portland, Oregon 97239, and 3 Department of
Psychiatry, Indiana University School of Medicine, Indianapolis,
Indiana 46202
Identifying and characterizing brain regions regulating alcohol
consumption is beneficial for understanding the mechanisms of
alcoholism. To this aim, we first identified brain regions changing in
expression of the inducible transcription factor c-Fos in the
alcohol-preferring C57BL/6J (B6) and alcohol-avoiding DBA/2J (D2) mice
after ethanol consumption. Drinking a 5% ethanol/10% sucrose solution
in a 30 min limited access procedure led to induction of c-Fos
immunoreactivity in urocortin (Ucn)-positive cells of the
Edinger-Westphal nucleus (EW), suppression of c-Fos immunoreactivity in
the dorsal portion of the lateral septum (LS) of both strains of mice,
and strain-specific suppression in the intermediate portion of the LS
and the CA3 hippocampal region. Because the EW sends Ucn projections to
the LS, and B6 and D2 mice differ dramatically in EW Ucn expression, we
further analyzed the Ucn EW-LS pathway using several genetic
approaches. We find that D2 mice have higher numbers of
Ucn-immunoreactive processes than B6 mice in the LS and that
consumption of ethanol/sucrose in the F2 offspring of a B6D2 intercross
positively correlates with Ucn immunoreactivity in the EW and
negatively correlates with Ucn immunoreactivity in the LS. In agreement
with these findings, we find that alcohol-avoiding male B6.D2
Alcp1 line 2.2 congenic mice have lower Ucn
immunoreactivity in the EW than male B6.B6 mice. Finally, we also find
that HAP mice, selectively bred for high alcohol preference, have
higher Ucn immunoreactivity in EW, than LAP mice, selectively bred for low alcohol preference. Taken together, these studies provide substantial evidence for involvement of the EW-LS Ucn pathway in
alcohol consumption.
Key words:
urocortin; ethanol; Edinger-Westphal; septum; inducible transcription factor; self-administration
Copyright © 2003 Society for Neuroscience 0270-6474/03/2362477-11$05.00/0