Development of catecholaminergic neurons of Otp-lineage in the medial extended amygdala and other centers of the social behavior network

Catecholaminergic (CA) neurons of the medial extended amygdala, preoptic region and adjacent alar hypothalamus have been involved in different aspects of social behavior. 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 to analyze coexpression of GFP and tyrosine hydroxylase (TH) throughout ontogenesis by way of double immunofluorescence. Our results showed that some TH cells coexpress GFP in the medial extended amygdala preoptic region, and alar and basal hypothalamus. However, the presence of TH/GFP double-labeled cells in the extended amygdala is transient, as they are not seen in adults. Based on previous data, the Otp-related CA cells of the medial extended amygdala might derive from the telencephalon-opto-hypothalamic domain, and those of the central paraventricular and supraoptic hypothalamic nuclei likely derive from the supraopto-paraventricular hypothalamic core domain. Taken together, these data provide new evidence for several Otp-related CA subpopulations in centers of the social brain network. The results open interesting questions about the role of these catecholaminergic subpopulations during the development and in different aspects of social behavior.