TYROSINE HYDROXYLASE POSITIVE CELLS IN THE PROSOMERIC HYPOTHALAMIC DOMAINS IN POSTNATAL RATS.

BILBAO MG; GARRIGÓS D; TOVAL JA; KUTSENKO Y; BAUTISTA R; BARREDA A; PUELLES L; FERRÁN JL.

Santiago de Compostela

Congreso; 18th National Meeting of the Spanish Society of Neuroscience; 2019

Sociedad Española de Neurocencia (SENC)

Tyrosine hydroxylase (TH) is the rate limiting step in the synthesis of catecholamines. This enzyme catalyzes the conversion of L-tyrosine into L-DOPA, a precursor of dopamine. Dopamine is a precursor of norepinephrine and epinephrine. Most of the well-known groups of TH positive cells are localized in diencephalic and mesencephalic (eg. A13, SNc and VTA), rhombencephalic (locus coeruleus) and telencephalic territories (OB). The expression of TH in the hypothalamic territory is mainly related with cells around the arcuate nucleus in the acroterminal domain (Puelles et al., 2012).With the aim to analyze in detail the TH/Th expression in hypothalamic domains and subdomains Sprague Dawley rats at postnatal stages were studied (P56 and P100). Immunohistochemistry and in situ hybridization for tyrosine in consecutive sections were compared with markers of specific hypothalamic nuclei (Pomc, Agrp, Avp, Oxt, Crh, Trh and Sst mRNA expression), combining in situ hybridization and immunohistochemistry on the same sections.In the paraventricular and subparaventricular alar domains Th/TH positive cells are most abundant within the periventricular layer at the level of the terminal portion, where some Th positive cells also can be observed in the intermediate layer, but such neurons are practically absent at the acroterminal portion and only few are present in the peduncular subregion. In the tuberal basal region most labelled cells are found in the neighborhood of the medial eminence (mainly arcuate nucleus), in the acroterminal domain, but some cell groups can be detected as well in the peduncular retrotuberal region, including the A13 cell group, as found in the mouse (Puelles et al., 2012). The prosomeric model was an excellent tool to determine precise localization of the Th/TH positive cells, a population that integrates into complex hypothalamic functions. Further functional hypothalamic experimental designs will be enriched integrating these dopaminergic neurons in the study of the specific nuclei functions.Supported by MEC/Feder grant BFU2014-57516P and 19904/GERM/15 SÉNECA Foundation (Community of Murcia) contract.