Fig. 3
The signalling pathway of AP-2β on catecholaminergic transmission where '–' symbolizes repressing and '+ ' activating effect of AP-2β on the transcription of its target genes. AP-2β stimulate the expression of key genes involved in catecholamine synthesis such as TH [33, 82, 89], DBH [33, 46, 82, 89, 90], PNMT [46, 86,87,88] while it lowers genes coding catecholamine degrading enzymes such as MAO [28, 91,92,93] and COMT [21, 92]. AP-2β also repress the transcription of DRD1A through binding to its D1AS1 [94]. AP-2β: transcription activating protein 2 beta; TH: tyrosine hydroxylase; DBH: dopamine-beta-hydroxylase; PNMT: phenylethanolamine N-methyltransferase; MAO: monoamine oxidase; COMT: catechol-O-methyltransferase; HVA: homovanillic acid; VMA: 3-methoxy-4-hydroxymandelic acid; MHPG: 3- methoxy-4-hydroxy-phenylglycol; D1AS1: dopamine receptor 1A silencer 1; DRD1A: dopamine receptor 1A; AC: adenylyl cyclase; and cAMP: cyclic adenosine monophosphate