Increased mRNA levels of tyrosine hydroxylase and dopamine transporter in the VTA of male rats after chronic food restriction.
Dieting as a strategy to reduce body weight often fails as it causes food cravings leading to bingeing and weight regain. Evidence from several lines of research suggests the presence of shared elements for neural regulation of food and drug craving. We quantified the expression of eight genes involved in dopamine signalling in brain regions related to the mesolimbic and nigrostriatal dopamine system in male rats subjected to chronic food restriction using quantitative real-time polymerase chain reaction. Food restriction strongly increased mRNA levels of tyrosine hydroxylase and the dopamine transporter in the ventral tegmental area. Quantitative autoradiography indicated that the dopamine transporter was also upregulated at the protein level in the shell of the nucleus accumbens. However, these effects were not observed after acute food deprivation. We suggest that the results reflect a sensitization of the mesolimbic dopamine pathway characterized by increased clearance of extracellular dopamine in the nucleus accumbens shell. Such sensitization of the mesolimbic dopamine system may be one of the underlying causes for the food cravings that interfere with dietary compliance.
Lindblom
Jonas
J
Department of Neuroscience, Uppsala University, Box 593 BMC, S-751 24 Uppsala, Sweden. Jonas.Lindblom@neuro.uu.se
Johansson
Andreas
A
Holmgren
Andreas
A
Grandin
Elisabeth
E
Nedergård
Carina
C
Fredriksson
Robert
R
Schiöth
Helgi B
HB
D000818:Animals; D001345:Autoradiography / Q000379:methods; D003042:Cocaine / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D005508:Food Deprivation; D015870:Gene Expression / Q000502:physiology*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism*; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000378:metabolism*
D050483:Dopamine Plasma Membrane Transport Proteins; D012333:RNA, Messenger; D019275:Radiopharmaceuticals; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D014446:Tyrosine 3-Monooxygenase; D003042:Cocaine