The metabolism of exogenous L-dopa in the brain: an immunohistochemical study of its conversion to dopamine in non-catecholaminergic cells of the rat brain.
The characterization and localization of non-catecholaminergic cells producing dopamine after L-Dopa load have been investigated in the normal rat brain by a direct immunohistochemical labelling of amines using specific antibodies. The detection of dopamine-containing non-catecholaminergic cells has been achieved in rats given a commonly used mixture of L-Dopa plus peripheral decarboxylase inhibitor, and compared to controls. Results indicate that serotoninergic neurons tend toward a switch of their metabolism into dopamine production after L-Dopa load in a dose-dependent manner. In addition small non-aminergic cells, identified as aromatic amino-acid decarboxylase-containing cells, were observed to produce dopamine after exogenous L-Dopa load. Possible implications of such results concerning the mode of action of L-Dopa in the brain are discussed.
Tison
F
F
Département de Neurologie, Hôpital Pellegrin, Bordeaux, France.
Mons
N
N
Geffard
M
M
Henry
P
P
D000284:Administration, Oral; D000818:Animals; D001545:Benserazide / Q000008:administration & dosage; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D007150:Immunohistochemistry; D007980:Levodopa / Q000008:administration & dosage / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D011903:Raphe Nuclei / Q000737:chemistry; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism; D013788:Thalamus / Q000737:chemistry
D012701:Serotonin; D007980:Levodopa; D001545:Benserazide; D004298:Dopamine