Fentanyl administration in infant rats produces long-term behavioral responses.
Considering the importance of studies in animal models that are focused on systems involved in pain mechanisms, this investigation aimed to evaluate the effects of pharmacological treatments on the behavioral responses of younger animals. To this end, we evaluated the effect of an acute dose of fentanyl (FEN) or S(+)-ketamine (KET) at postnatal day 14 (P14) upon behavioral responses in the short- (P14), medium- (P30) and long-term (P60) using the open field (OF), elevated plus-maze (EPM) and formalin tests (FT) and tail-flick latency. Fourteen-day-old male Wistar rats were divided into three groups: control (CT), fentanyl (FEN) and S(+)ketamine (KET) groups for statistical analysis, it was performed two-way ANOVA followed by Bonferroni. We found that, regardless of the test performed (OF or EPM), between-group differences occurred over time in all behaviors analyzed, including in the second phase of FT. In addition, EPM showed significant differences in behavioral responses related to acute administration (at P14) of fentanyl or S(+)-ketamine, in behaviors such as number of entries in open and closed arms, time spent in open and closed arms, and number of head-dipping. In relation to nociceptive response, the FEN group exhibited a decrease in the first phase of FT. These results indicate that unique administration of fentanyl or S(+)ketamine in an early period of life (P14) can promote changes in behavioral responses. In addition, our findings highlight the importance of extending the investigation of the effect of drug administration in young rats into adulthood.
Laboratory of Pharmacology of Pain, Department of Pharmacology, Institute of Basic Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), 90050-170 Porto Alegre, RS, Brazil.
Liciane Fernandes
LF
Medeiros
Ana Cláudia
AC
de Souza
Andressa
A
de Souza
Stefania Giotti
SG
Cioato
Vanessa Leal
VL
Scarabelot
Wolnei
W
Caumo
Luciana Carvalho
LC
Fernandes
Iraci L S
IL
Torres
D000701:Analgesics, Opioid / Q000494:pharmacology; D000778:Anesthetics, Dissociative / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D004195:Disease Models, Animal; D005283:Fentanyl / Q000494:pharmacology*; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D059408:Pain Management / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D013995:Time
D000701:Analgesics, Opioid; D000778:Anesthetics, Dissociative; D007649:Ketamine; D005283:Fentanyl