Mouse neuroblastoma clone N1E-115: a suitable model for studying the action of dopamine agonists of tyrosine hydroxylase activity.
The DOPA-content in neuroblastoma clone N1E-115 is higher than the dopamine or noradrenaline content. Blockade of tyrosine hydroxylase by alpha-methyl-p-tyrosine (1 X 10(-3) M) resulted in a decrease of cellular DOPA-content to 24.9% after 4 hr. The accumulation of DOPA in these cells which is probably due to limited activity of l-aromatic amino acid decarboxylase led us to use DOPA-content as a measure of tyrosine hydroxylase (TH) activity. Dopamine and especially apomorphine were effective at low concentrations (dopamine IC50 1 X 10(-5) M, apomorphine 2 X 10(-7) M); lisuride had no effect on TH-activity. The low effective dose of apomorphine and the failure of lisuride to influence TH-activity are comparable to the observations in striatal synaptosomal preparations and make the N1E-115 clone a suitable model for studying the mechanism of TH-regulation. However, since haloperidol (1 X 10(-5) M) did not reverse the apomorphine-induced blockade of TH, a receptor-mediated blockade of TH seems to be improbable.
D000818:Animals; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism; D002478:Cells, Cultured; D002999:Clone Cells; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D004298:Dopamine / Q000502:physiology*; D051379:Mice; D009374:Neoplasms, Experimental / Q000201:enzymology; D009447:Neuroblastoma / Q000201:enzymology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D002395:Catecholamines; D004295:Dihydroxyphenylalanine; D014446:Tyrosine 3-Monooxygenase; D001142:Aromatic-L-Amino-Acid Decarboxylases; D004298:Dopamine