title: Short-term cold exposure activates TRH neurons exclusively in the hypothalamic paraventricular nucleus and raphe pallidus.
abstract: The neuropeptide thyrotropin releasing hormone (TRH) is necessary for adequate cold-induced thermogenesis. TRH increases body temperature via both neuroendocrine and autonomic mechanisms. TRH neurons of the hypothalamic paraventricular nucleus (PVN) regulate thermogenesis through the activation of the hypothalamic-pituitary-thyroid axis during cold exposure. However, little is known about the role that TRH neurons play in mediating the sympathetic response to cold exposure. Here, we examined the response of TRH neurons of rats to cold exposure in hypothalamic regions including the PVN, the dorsomedial nucleus and the lateral hypothalamus along with areas of the ventral medulla including raphe obscurus, raphe pallidus (RPa) and parapyramidal regions. Our results using a double immunohistochemistry protocol to identify TRH and c-Fos (as a marker of cellular activity) followed by analysis of preproTRH gene expression demonstrate that only TRH neurons located in the PVN and the RPa are activated in animals exposed to short-term cold conditions.
authors.affiliation: Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (CONICET/CICPBA), La Plata, Argentina.
authors.forename: Agustina
authors.initials: A
authors.lastname: Cabral
authors.forename: Spring
authors.initials: S
authors.lastname: Valdivia
authors.forename: Mirta
authors.initials: M
authors.lastname: Reynaldo
authors.forename: Nicole E
authors.initials: NE
authors.lastname: Cyr
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Nillni
authors.forename: Mario
authors.initials: M
authors.lastname: Perello
mesh_terms: D000818:Animals; D003080:Cold Temperature; D007031:Hypothalamus / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D022722:Thermogenesis / Q000502:physiology*; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism*
chemical_list: D013973:Thyrotropin-Releasing Hormone