Development of catecholaminergic neurons of Otp-lineage in the medial extended amygdala and related forebrain centers

Abstract

Catecholaminergic (CA) neurons of the medial extended amygdala, preoptic region and adjacent alar hypothalamus have been involved in different aspects of social behavior, as well as in modulation of homeostasis in response to different stressors. Previous data suggested that at least some CA neurons of the medial extended amygdala could originate in a hypothalamic embryonic domain that expresses the transcription factor Otp. To investigate this, we used Otp-eGFP mice (with permanent labeling of GFP in Otp cells) to analyze coexpression of GFP and tyrosine hydroxylase (TH) throughout ontogenesis by way of double immunofluorescence. Our results provide evidence that some forebrain CA cells belong to the Otp lineage. In particular, we found small subpopulations of TH cells that coexpress GFP within the medial extended amygdala, the periventricular preoptic area, the paraventricular hypothalamus, the periventricular hypothalamus, as well as some subdivisions of the basal hypothalamus. In some of the Otp cells, such as those of extended amygdala, the expression of TH appears to be transitory, in agreement with previous studies. The results open interesting questions about the role of these Otp versus non-Otp catecholaminergic subpopulations during development, network integration and in modulation of different functions, including homeostasis and social behaviors.

The author(s) declare that financial support was received for the research and/or publication of this article. Funded by the Spanish Ministerio de Ciencia, Innovación y Universidades and Agencia Estatal de Investigación, MICIU/AEI/10.13039/501100011033 and FEDER-EU (Grants no. PID2019-108725RB-100 and no. PID2023- 151927OB-I00), and by the AGAUR/Generalitat de Catalunya (2021 SGR 01359). Lorena Morales had predoctoral contracts from Universitat de Lleida Ajuts Jade Plus, and from IRBLleida/Diputació de Lleida. Currently, Lorena Morales is funded by European Union’s Horizon 2020 Research and Innovation Programme under the INSPIRE COFUND Marie Skłodowska-Curie grant agreement No. 101034270. ED is fellow of the Serra Húnter Senior Programme of the Catalonia Goverment for distinguished professors of Catalan public universities.