Gamma-butyrolactone-induced dopamine accumulation in prefrontal cortex is affected by tyrosine availability.
Gamma-butyrolactone (GBL) elevates striatal and prefrontal cortex dopamine levels; only the striatal dopamine levels are elevated by increased dopamine synthesis. If increased dopamine synthesis is necessary in order for dopamine levels to be affected by tyrosine availability, then GBL-induced prefrontal cortex dopamine levels should be tyrosine insensitive. Rats received either vehicle, tyrosine (50 or 200 mg/kg i.p.) or a tyrosine-depleting mixture prior to GBL 750 mg/kg i.p.. GBL-induced dopamine levels in prefrontal cortex were lowered by tyrosine depletion. GBL-induced striatal dopamine levels were not affected. Hence, increased dopamine synthesis may not be necessary in order for tyrosine availability to affect pharmacologically elevated prefrontal cortex dopamine levels.
Jaskiw
George E
GE
Psychiatry Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44141, USA. gxj5@case.edu <gxj5@case.edu>
Newbould
Erica
E
Bongiovanni
Rodolfo
R
D015107:4-Butyrolactone / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001479:Basal Ganglia / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D008297:Male; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine / Q000172:deficiency / Q000378:metabolism*; D015854:Up-Regulation
D014443:Tyrosine; D015107:4-Butyrolactone; D004298:Dopamine