Inhibition of TkB synthesis blocks axogenic effect of estradiol on hypothalamic neurons in vitro

BRITO, V.; CARRER, H.F.; CAMBIASSO, M.J.

EUROPEAN JOURNAL OF NEUROSCIENCE

Blackwell Science

Año: 2004 vol. 20 p. 331 - 337

0953-816X

17-b-estradiol (E2) increases axonal growth and TrkB levels of male derived hypothalamic neurons in vitro. To investigate whether the axogenic response depends on the upregulation of TrkB, we analyzed neuritic growth and neuronal polarization in cultures treated with an antisense oligonucleotide against TrkB mRNA. In cultures without E2, treatment with 7.5 or 10 mM antisense reduced TrkB levels and the percentage of neurons showing an identifiable axon; number and length of minor processes were increased. In cultures treated with 5 mM antisense, morphometric parameters were normal although total TrkB levels were reduced. The same dose prevented the E2-dependent increase of TrkB levels and suppressed the axogenic effect of  E2. These results indicate that TrkB is necessary for normal neuronal growth and maturation and further suggest that an increase in TrkB is necessary for E2 to exert its axogenic effect in male derived neurons.