title: Gender-dependent effect on nociceptive response induced by chronic variable stress.
abstract: It has previously been reported that exposure to repeated restraint stress induces hyperalgesia in male rats, an effect that was not observed in females. The aim of the present study was to investigate the effects of chronic variable stress over 40days on nociception threshold indexed by tail-flick latency in male and female adult rats. The results showed different behavior in chronically stressed animals when compared to the control group: male rats showed a decrease in tail-flick latency while females presented an increase in this parameter. For female rats this effect was independent of the phase of the estrous cycle. Several sources of data indicate that behavioral and physiological responses to stress are sexually dimorphic, including in nociception, and the estrous cycle appears to be a factor that influences opioid analgesia in female. These effects are modulated by the strain and conditions of nociception assay. Additional studies concerning the mechanisms involved in the hyperalgesic response in males and the differences on nociceptive response in females chronically exposed to stress are needed.
authors.affiliation: Departamento de Bioquímica, Centro de Ciências Químicas, Farmacêuticas e de Alimentos, UFPel, Campus Capão do Leão S/N, Prédio 29 sala 303 Caixa Postal 354, 96010-900, Pelotas, RS, Brazil. Electronic address: ggamaro@yahoo.com.br.
authors.forename: G D
authors.initials: GD
authors.lastname: Gamaro
authors.affiliation: Laboratório de Farmacologia da Dor e Neuromodulação: Modelos Animais, Departamento de Farmacologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, CEP 90050-170, Porto Alegre, Brazil.
authors.forename: I L S
authors.initials: IL
authors.lastname: Torres
authors.affiliation: Laboratório de Farmacologia da Dor e Neuromodulação: Modelos Animais, Departamento de Farmacologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, CEP 90050-170, Porto Alegre, Brazil.
authors.forename: G
authors.initials: G
authors.lastname: Laste
authors.affiliation: Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, ANEXO Lab 34 CEP 90035-003, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: F U
authors.initials: FU
authors.lastname: Fontella
authors.affiliation: Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, ANEXO Lab 34 CEP 90035-003, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: P P
authors.initials: PP
authors.lastname: Silveira
authors.affiliation: Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, ANEXO Lab 34 CEP 90035-003, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: L P
authors.initials: LP
authors.lastname: Manoli
authors.affiliation: Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, ANEXO Lab 34 CEP 90035-003, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: F
authors.initials: F
authors.lastname: Frantz
authors.affiliation: Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, ANEXO Lab 34 CEP 90035-003, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: F
authors.initials: F
authors.lastname: Eickhoff
authors.affiliation: Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, ANEXO Lab 34 CEP 90035-003, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Dalmaz
mesh_terms: D000818:Animals; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D006930:Hyperalgesia / Q000503:physiopathology*; D008297:Male; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors; D013315:Stress, Psychological / Q000503:physiopathology*
keywords: Chronic variable stress; Estrous cycle; Gender; Nociception; Rats; Stress