ONTOGENY OF THE CELL OUTWARD DOPAMINE TRANSPORTER IN CANINE RENAL TISSUES

• Tipo: Artigo em Revista Científica Internacional
• Data: 1995

Autores

soaresdasilva, p (Autor) Outra; vieiracoelho, ma (Autor) Outra; pestana, m (Autor) FMUP; fernandes, mh (Autor) FMDUP; guimaraes, jt (Autor) FMUP

Revista

Título: Fundamental and Clinical Pharmacology

Vol. 9

Páginas: 255-262

ISSN: 0767-3981

Editora: Wiley-Blackwell

Indexação

ISI Web of Knowledge - 4 Citações

Scopus - 4 Citações

Classificação Científica

FOS: Ciências médicas e da saúde > Medicina básica

Outras Informações

ID Authenticus: P-001-HP7

DOI: 10.1016/0767-3981(96)80355-0

Abstract (EN): The present work has determined the activities of aromatic L-amino acid decarboxylase (AAAD) and evaluated the presence of an active transport system for dopamine in renal tissues of developing dogs (newborn puppies less than 24 hours after birth, animals at the age of 10 days and 2 months) and adult animals. AAAD activity (V-max, in pmol/mg protein/h) as determined in kidney homogenates was found to be in the adult dog kidney (V-max = 3216 +/- 268) higher (p < 0.05) than that occurring in the three other groups of animals; no significant difference on AAAD activity was observed between the 10 day-old (V-max = 1139 +/- 185) and the 2 month-old dogs (V-max = 783 +/- 23). AAAD activity in newborn puppies (V-max = 259 +/- 40) was markedly lower than in the three other groups. A considerable amount of the total dopamine formed from added L-DOPA in kidney slices, depending on the age, was found to escape into the incubation medium. The application of the Michaelis-Menten equation to the net transport of newly-formed dopamine has allowed the identification of a saturable (carrier-mediated transfer) and a non-saturable component (diffusion). The V-max (nmol/g/15 min), K-m (mu M) values for the saturable component and diffusion constant mu mol(-1)) were as follows: adult (V-max = 112 +/- 16; K-m = 319 +/- 35; diffusion constant = 0.0009 +/- 0.0001), 2 month-old (V-max = 19 +/- 5; K-m = 48 +/- 14; diffusion constant = 0.0007 +/- 0.0002), 10 day-old (V-max = 25 +/- 3; K-m = 69 +/- 20; diffusion constant = 0.0033 +/- 0.0007) and newborn (V-max = 6 +/- 1; K-m = 16 +/- 6; diffusion constant = 0.0095 +/- 0.0010). In conclusion, renal AAAD develops with age, though some AAAD activity can already be detected at birth. The dopamine outward transporter appears to be considerably immature at birth, but undergoes rapid maturation within the next 10 days; however, development of AAAD and of the renal dopamine outward transporter still proceedes from the age of 2 months until adulthood.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 8