title: Brain Temperature in Spontaneously Hypertensive Rats during Physical Exercise in Temperate and Warm Environments.
abstract: This study aimed to evaluate brain temperature (Tbrain) changes in spontaneously hypertensive rats (SHRs) subjected to two different physical exercise protocols in temperate or warm environments. We also investigated whether hypertension affects the kinetics of exercise-induced increases in Tbrain relative to the kinetics of abdominal temperature (Tabd) increases. Male 16-week-old normotensive Wistar rats (NWRs) and SHRs were implanted with an abdominal temperature sensor and a guide cannula in the frontal cortex to enable the insertion of a thermistor to measure Tbrain. Next, the animals were subjected to incremental-speed (initial speed of 10 m/min; speed was increased by 1 m/min every 3 min) or constant-speed (60% of the maximum speed) treadmill running until they were fatigued in a temperate (25°C) or warm (32°C) environment. Tbrain, Tabd and tail skin temperature were measured every min throughout the exercise trials. During incremental and constant exercise at 25°C and 32°C, the SHR group exhibited greater increases in Tbrain and Tabd relative to the NWR group. Irrespective of the environment, the heat loss threshold was attained at higher temperatures (either Tbrain or Tabd) in the SHRs. Moreover, the brain-abdominal temperature differential was lower at 32°C in the SHRs than in the NWRs during treadmill running. Overall, we conclude that SHRs exhibit enhanced brain hyperthermia during exercise and that hypertension influences the kinetics of the Tbrain relative to the Tabd increases, particularly during exercise in a warm environment.
authors.affiliation: Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil.|Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: Lucas Rios
authors.initials: LR
authors.lastname: Drummond
authors.affiliation: Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: Ana Cançado
authors.initials: AC
authors.lastname: Kunstetter
authors.affiliation: Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: Filipe Ferreira
authors.initials: FF
authors.lastname: Vaz
authors.affiliation: Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: Helton Oliveira
authors.initials: HO
authors.lastname: Campos
authors.affiliation: Laboratório de Biomecânica, Departamento dos Esportes, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: André Gustavo Pereira
authors.initials: AGP
authors.lastname: de Andrade
authors.affiliation: Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: Cândido Celso
authors.initials: CC
authors.lastname: Coimbra
authors.affiliation: Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil.
authors.forename: Antônio José
authors.initials: AJ
authors.lastname: Natali
authors.affiliation: Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: Samuel Penna
authors.initials: SP
authors.lastname: Wanner
authors.affiliation: Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil.
authors.forename: Thales Nicolau
authors.initials: TN
authors.lastname: Prímola-Gomes
mesh_terms: D000818:Animals; D001831:Body Temperature; D001921:Brain / Q000503:physiopathology*; D005080:Exercise Test / Q000379:methods*; D005221:Fatigue / Q000503:physiopathology*; D005334:Fever / Q000175:diagnosis*; D006973:Hypertension / Q000503:physiopathology* / Q000662:veterinary; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D012420:Running; D013696:Temperature