title: Evidence for adrenal medulla involvement in cold adaptation of preoptic-lesioned rats.
abstract: The cold-adaptation process was examined in preoptic-lesioned (PO, 18 rats) and adrenaldemedullated-preoptic-lesioned rats (ADPO, 16 rats). PO rats and ADPO female Wistar rats were cold acclimatized to 5 degrees C for 2 operated and then treated exactly like the lesioned rats. Lesions in the PO region caused a decrease in the ability to maintain normal body temperature in a cold environment (5 degrees C for 2 h). Their colonic temperature fell even by the end of the 2nd h of cold exposure (-1.1 degrees C for PO rats and -1.25 degrees C for ADPO rats, P less than 0.01). However, after 2 weeks of cold acclimation the PO rats, but not the ADPO rats were able to thermoregulate in the cold and showed a normal increase in interscapular brown adipose tissue weight (79%, P less than 0.01). These data suggest that the PO is not an essential link for cold adaptation when a mild cold-adaptation method is used. Furthermore, the data show that increased adrenal medullary activity is required for the cold adaptation process in PO rats.
authors.affiliation: Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
authors.forename: A N
authors.initials: AN
authors.lastname: Martins
authors.forename: M V
authors.initials: MV
authors.lastname: Blom
authors.forename: A M
authors.initials: AM
authors.lastname: Reis
authors.forename: C C
authors.initials: CC
authors.lastname: Coimbra
mesh_terms: D000222:Adaptation, Physiological; D000313:Adrenal Medulla / Q000502:physiology*; D000818:Animals; D001833:Body Temperature Regulation; D003080:Cold Temperature; D005260:Female; D011301:Preoptic Area / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains