Fentanyl administration in infant rats produces long‐term behavioral responses

Abstract

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.

A Single Neonatal Injury Induces Life-Long Deficits in Response to Stress

“…These data are the first mechanistic demonstration that early-life inflammatory pain changes adult responses to stress through alterations in the endogenous opioid system. Moreover, these data contribute to the growing number of animal studies addressing issues surrounding early-life pain, analgesia and anesthesia and their long-term consequences [19,42,43,44,45,46]. …”

Transcranial direct current stimulation (tDCS) reverts behavioral alterations and brainstem BDNF level increase induced by neuropathic pain model: Long-lasting effect

“…The linoleum floor was divided by dark lines into twelve 13 × 13 cm squares. Each trial started immediately after the animals were placed in the back left corner and allowed to explore the surroundings for 5 min (Bianchin et al, 1994;Medeiros et al, 2012). The box was cleaned between trials.…”

One-time Exposure to General Anesthetics Alters Nociceptive Response and Nucleotide Hydrolysis in Infant Rats

“…Therefore, both fibers occupy the same space within the spinal cord [40]. Interestingly, our previous study [14] showed that when we used fentanyl or S(+)-ketamine alone at P14, no differences in the tail-flick latency test were observed, regardless of the age analyzed (P14 or P30). In the present study, the fentanyl/S-(+)-ketamine administered at P14 was capable of promoting an analgesic response at P30.…”

“…The evaluation of possible physiological effects after general anesthetic exposure is an area of clinical interest. Our previous studies demonstrated that the unique administration of general anesthetics during early life is capable of producing short-, intermediate-, and longterm behavioral alterations [13,14]. Thus, due to the close relationship between purinergic enzymes and the cellular membrane (the membrane may be involved with the mechanism of action of general anesthetics), our present study evaluated the effect of a single exposure to general anesthetic (inhalator and intra-peritoneal) at postnatal day fourteen (P14), with or without performing a surgical procedure in the E-NTPDases and ecto-5'nucleotidase activities and in the nociceptive responses.…”