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Expression of members of the trk family in the developing postnatal rat brain

1993; Elsevier BV; Volume: 72; Issue: 1 Linguagem: Inglês

10.1016/0165-3806(93)90165-7

1872-6755

Thomas Ringstedt, Hugo Lagercrantz, Håkan Persson,

Neurogenesis and neuroplasticity mechanisms

Tyrosine protein kinases trk, trk B and trk C are essential components of the high affinity receptors necessary to mediate biological effects of the neurotrophins NGF, BDNF, NT-3 and NT-4. Here we report on the expression of these receptors during postnatal development in the rat brain. Cells expressing mRNAs encoding different members of the trk family were identified by in situ hybridization using oligonucleotides complementary to their respective mRNA. In septum, striatum and brainstem, higher levels of trk mRNA were detected at 2 and 4 weeks than at 1 weeks of age. In thalamic nuclei associated with the limbic system, trk B and trk C mRNA were highly expressed at P1 to P7, but the expression declined gradually in 2 and 4 week old animals. Other structures where a developmentally regulated expression was seen included the tenia tecta and piriform cortex where trk B mRNA was not detected until 2 weeks of age. A high labeling was found for trk C mRNA in the deeper parts of neocortex in P1 and P4 animals, while in 2 and and 4 weeks old animals the highest labeling was seen over the outer neocortical layers. Several brainstem nuclei showed a higher labeling for trk C mRNA at P1 to P7 than in animals of older age. These data show that expression of members of the trk family is developmentally regulated during postnatal brain development and suggest that high affinity neurotrophin receptors mediate a transient response to neurotrophins in many regions during brain ontogeny.