Tryptophan metabolism in male Sardinian alcohol-preferring (sP) and -non-preferring (sNP) rats.
Parameters of tryptophan (Trp) and related metabolism were compared in male Sardinian alcohol-preferring (sP) and -non-preferring (sNP) rats. Liver Trp pyrrolase activity was 38-58% higher in sP than in sNP rats, and this was associated with a greater expression of the enzyme mRNA as measured by multiprobe oligonucleotide solution hybridization. Moderately (about 10-19%), but significantly, lower concentrations of free serum, total serum, and brain Trp were also observed in sP compared with sNP rats. Concentrations of whole brain 5-hydroxytryptamine (5-HT) and its major metabolite 5-hydroxyindol-3-yl-acetic acid (5-HIAA) were, however, 14-21% higher in sP rats. Serum corticosterone concentration was 18% higher in sP rats. We conclude that alcohol preference in Sardinian rats is associated with increased liver Trp pyrrolase activity and mRNA expression leading to a decrease in Trp availability to the brain. Although a simple serotonin deficiency could not be demonstrated in the whole brain, the possibility could not be ruled out that a deficiency may be present in discrete areas of the brain of the sP rat.
Bano
S
S
Division of Psychological Medicine, University of Wales College of Medicine, Heath Park, Cardiff, UK.
Morgan
C J
CJ
Badawy
A A
AA
Colombo
G
G
Buckland
P R
PR
McGuffin
P
P
Fadda
F
F
Gessa
G L
GL
D000437:Alcoholism / Q000201:enzymology* / Q000235:genetics; D000818:Animals; D001921:Brain / Q000201:enzymology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D005838:Genotype; D006897:Hydroxyindoleacetic Acid / Q000097:blood; D008099:Liver / Q000201:enzymology*; D008297:Male; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000097:blood; D014364:Tryptophan / Q000097:blood*; D014366:Tryptophan Oxygenase / Q000097:blood* / Q000235:genetics
D012333:RNA, Messenger; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan; D014366:Tryptophan Oxygenase