title: Experimental hypothyroidism during pregnancy affects nociception and locomotor performance of offspring in rats.
abstract: BACKGROUND
  Thyroid hormones (THs) play a crucial role in the development of several organic systems. An adequate support of maternal THs may be required to ensure a normal nociceptive function of offspring into adulthood. We investigated the impact of experimental gestational hypothyroidism (EGH) on nociceptive threshold and motor performance in the offspring at different post-natal days (PND) in both male and female rats.
  
  
  METHODS
  EGH was induced by the administration of 0.02% methimazole (MMI) in the drinking water from the ninth day of gestation until birth. The offspring from MMI-treated dams (OMTDs) or from water-treated dams (OWTDs) were assessed for thermal and mechanical nociception using the tail-flick test and von Frey filaments, respectively. Both rota-rod and grip strength were used to assess motor function.
  
  
  RESULTS
  OMTD had reduced thermal (p<0.05) but not mechanical threshold at all studied ages (60 and 120 PND). Sixty-day-old OMTD presented reduced latency to the tail-flick test (p=0.01). Grip strength in 120-day-old OMTD was reduced (p<0.01). However, only male OMTD presented a lower locomotor performance on the rota-rod test when analysed on the 60th PND (p<0.01).
  
  
  CONCLUSIONS
  EGH promotes hypersensitivity to noxious thermal but not mechanical stimulus. Moreover, motor force is similarly reduced in male and female OMTDs, whereas motor performance is reduced only in mature male OMTD, suggesting the presence of a protective factor in females.
authors.affiliation: Departamento de Fisiologia, Universidade Federal de Sergipe, Aracaju, Brazil.
authors.forename: I G N
authors.initials: IG
authors.lastname: Alves
authors.forename: K M L
authors.initials: KM
authors.lastname: da Cruz
authors.forename: C M D
authors.initials: CM
authors.lastname: Mota
authors.forename: D S
authors.initials: DS
authors.lastname: de Santana
authors.forename: D P
authors.initials: DP
authors.lastname: Gaujac
authors.forename: V C B
authors.initials: VC
authors.lastname: de Carvalho
authors.forename: L C
authors.initials: LC
authors.lastname: Reis
authors.forename: K A
authors.initials: KA
authors.lastname: Sluka
authors.forename: L J
authors.initials: LJ
authors.lastname: Quintans-Junior
authors.forename: A R
authors.initials: AR
authors.lastname: Antoniolli
authors.forename: J M
authors.initials: JM
authors.lastname: Desantana
authors.forename: D
authors.initials: D
authors.lastname: Badauê-Passos
authors.forename: V J
authors.initials: VJ
authors.lastname: de Santana-Filho
mesh_terms: D000818:Animals; D005260:Female; D007037:Hypothyroidism / Q000150:complications / Q000503:physiopathology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D059225:Nociception / Q000502:physiology*; D010146:Pain / Q000209:etiology / Q000503:physiopathology*; D010147:Pain Measurement; D010812:Physical Stimulation; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar