Neonatal morphine exposure and maternal deprivation alter nociceptive response and central biomarkers’ levels throughout the life of rats (original) (raw)

Chronic paternal morphine exposure increases sensitivity to morphine-derived antinociception

2021

Parental exposure to drugs of abuse such as opioids can have profound and long-lasting effects on reward processing and drug sensitivity across generations. However, little is known about the impact of long-term paternal exposure to morphine on offspring sensitivity to morphine-derived antinociception during painful experiences. To address this question, we constructed a rat pain scale at millisecond timescales to measure mechanical nociception in a multigenerational morphine exposure paradigm. Surprisingly, while developing the pain scale, we found that von Frey hair filaments (VFHs), the most common stimuli used in pain research, are not painful to rats and morphine did not change the touch-like responses elicited by VFHs. We next deployed this novel pain scale to determine whether chronic morphine exposure in sires impacted pain sensitivity in the next generation. Offspring produced from a cross of morphine-treated sires and drug-naïve dams, did not show any baseline changes in s...

Effects of postnatal manipulation on nociception and morphine sensitivity in adult mice

Developmental Brain Research, 1999

The long-term effects of postnatal manipulation on nociception were studied in NMRI albino male mice. During the first two weeks of life, pups were removed from their cage and deprived of maternal/nest odour for 15 min/day. To evaluate pain sensitivity, adult mice exposed to this postnatal manipulation (CB group) were tail flick and formalin tested for acute and tonic pain, respectively. CB mice showed a reduced pain sensitivity both in tail-flick and in formalin tests in comparison with control animals. Moreover, responsiveness to morphine (MO 1.0, 2.5, and 5.0 mg/kg, i.p.) in young (35 days old) and adult (90 days old) postnatally manipulated animals was evaluated with the tail-flick test: a decrease of the antinociceptive effects induced by morphine both in young and adult males was observed in postnatally manipulated animals. Morphine induced significant analgesic effects in control mice at doses lower than those affecting nociceptive thresholds both in young and adult CB mice. In addition, young animals showed a higher sensitivity to morphine than adults, independently of postnatal manipulation. The long-term effects of postnatal manipulation on nociception are discussed in terms of involvement of the opioid system and of the characteristics of pup manipulation.

Influence of early neonatal experience on nociceptive responses and analgesic effects in rats

Laboratory Animals, 2009

Early maternal separation has profound effects on nociception in rats. Cross-fostering is a standard husbandry procedure used by some commercial breeders. This study aimed to determine if cross-fostering altered nociception and the analgesic efficacy of buprenorphine and morphine. At seven and nine weeks of age, an elevated plus maze was used to assess anxiety and Hargreaves apparatus was used to measure thermal nociception at two intensities in cross-fostered and naturally-reared rats. At 10 weeks of age these rats were assigned to one of three treatment groups: saline, buprenorphine or morphine. The Hargreaves apparatus was used to evaluate the effect of analgesics on nociception. Differences were observed in nociception between the cross-fostered and naturally-reared rats at both intensities. At the lower intensity no significant differences were seen between the cross-fostered and naturally-reared rats post-administration of an analgesic. At the higher intensity significant diff...