Molecular and functional diversity within hindbrain serotonergic (5-HT) neurons has emerged as a relevant feature that could underlie selective vulnerability of neurons in clinical disorders. We have investigated the role of transforming growth factor beta 2 (TGF-b2) during development of mouse hindbrain 5-HT subgroups. Therefore, we performed a phenotypic analysis during development of the hindbrain serotonergic system in TGF-b2 mutant mice. The results show a significant decrease in the number of 5-HT neuronsin TGF-b2-deficient mice at embryonic day (E) 12, whereas at E14 and E16 the number of 5-HT neurons was comparable between wildtype and mutant mice. At E18a selective significant decrease in the hindbrain paramedianraphe 5-HT neurons in the mutant was observed, compared to wildtype.
These resultshighlight a selective growth factor dependency of individual rostral hindbrain serotonergic subpopulations,emphasize the impact of TGF-b2 during development of 5-HT subgroups, and suggest TGF-b2as potent candidate to establish diversity within the hindbrain serotonergic system.