A. Nicotra et al., Ontogeny of monoamine oxidase A and B activities in developing chick cerebellum: a biochemical study, BIOG AMINE, 15(5), 2000, pp. 489-501
This study aims at characterizing the temporal evolution of MAO A and MAO B
activities in developing chick cerebellum. In a first series of experiment
s carried out in embryos at different stages and in one month-old chickens,
we examined the inhibition dose-response curves obtained with clorgyline (
a selective inhibitor of MAO A) and l-deprenyl (a selective inhibitor of MA
O B) using serotonin (5-HT) and beta-phenylethylamine (PEA) as substrates.
The results obtained demonstrated that also in our system 5-HT was preferen
tially deaminated by MAO A and PEA by MAO B. 5-HT and PEA were thus used in
order to measure changes in MAO A and MAO B specific activities in cerebel
la of embryos sacrificed daily from E10 until hatching (E21) and from one m
onth-old chickens, In embryos at E10 MAO B activity was significantly highe
r than MAO A activity. At subsequent stages MAO A and MAO B activities foll
owed different patterns indicating different developmental regulation. The
study of the kinetic parameters ( K-m and V-max) suggested that observed ch
anges in enzyme specific activities mainly reflect variable enzyme amounts.