Developmental regulation of the serotonergic transmitter phenotype in rostral and caudal raphe neurons by transforming growth factor-βs
✍ Scribed by Dagmar Galter; Martina Böttner; Klaus Unsicker
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 195 KB
- Volume
- 56
- Category
- Article
- ISSN
- 0360-4012
No coin nor oath required. For personal study only.
✦ Synopsis
Serotonergic (5-HT) neurons of the CNS develop as two separate clusters, a rostral and a caudal group, within the brain stem raphe. We show here that the transforming growth factors -2 and -3 (TGF-) and the TGF- type II receptor are expressed in the embryonic rat raphe, when 5-HT neurons develop and differentiate. To investigate putative roles of TGF-s in the regulation of 5-HT neuron development we have generated serum-free cultures isolated either from the rostral or the caudal embryonic rat raphe, respectively. In cultures from the caudal E14 raphe saturating concentrations (5 ng/ml) of TGF-2 and -3 augmented numbers of tryptophan hydroxylase (TpOH) -immunoreactive neurons and cells specifically taking up 5,7-dihydroxytryptamine (5,7-DHT) by about 1.7-fold over a period of 4 days. Treatment with TGF-s also increased uptake of 3 H-5HT uptake about 1.7-fold. Alterations in 5-HT neuron numbers were due to the induction of serotonergic markers rather than increased survival, as shown by the efficacy of delayed short-term treatments. Comparing rostral and caudal raphe cultures from different embryonic ages suggests that distinct effects of TGF-s reflect the responsiveness of 5-HT neurons at different ages rather than of different origins.