Differentiation of tyrosine hydroxylase-synthesizing and/or aromatic L-amino acid decarboxylase-synthesizing neurons in the rat mediobasal hypothalamus: quantitative double-immunofluorescence study.
In this double-immunofluorescence study, we first quantified the neurons of the arcuate nucleus as immunoreactive (+) for tyrosine hydroxylase (TH) and/or aromatic L-amino acid decarboxylase (AADC) in rats at embryonic day 21 (E21), at postnatal day 9 (P9), and in adulthood by using conventional fluorescent or confocal microscopy. On E21, monoenzymatic (TH(+)AADC immunonegative (-) and TH(-)AADC(+)) neurons and bienzymatic (TH(+)AADC(+)) neurons accounted for 99% and 1%, respectively, of the whole neuron population expressing enzymes of dopamine synthesis. Further development was characterized by the dramatic increase in TH(+)AADC(-) dorsomedial and TH(+)AADC(+) dorsomedial populations from E21 to P9 as well as by the increase in the TH(+)AADC(+) dorsomedial population (in females) and a drop in the TH(+)AADC(-) ventrolateral and TH(+)AADC(-) dorsomedial (in males) populations from P9 to adulthood. In contrast to TH(+)AADC(-) (in males) and TH(+)AADC(+) neurons, the TH(-)AADC(+) neurons did not change in number from E21 to adulthood. Thus, in rat fetuses, the neurons synthesizing TH and/or AADC were mainly monoenzymatic, whereas during postnatal life the fraction of bienzymatic neurons increased by up to 60%.
Ershov
Petr V
PV
Laboratory of Neurohistology, Institute of Normal Physiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
Ugrumov
Michael V
MV
Calas
André
A
Krieger
Monique
M
Thibault
Jean
J
D000367:Age Factors; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology / Q000201:enzymology*; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000032:analysis* / Q000276:immunology; D002452:Cell Count / Q000379:methods; D004298:Dopamine / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D008297:Male; D009474:Neurons / Q000201:enzymology*; D010904:Pituitary Gland, Posterior / Q000201:enzymology; D051381:Rats; D017208:Rats, Wistar / Q000378:metabolism*; D012727:Sex Characteristics; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis* / Q000276:immunology
D014446:Tyrosine 3-Monooxygenase; D001142:Aromatic-L-Amino-Acid Decarboxylases; D004298:Dopamine