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Peri, pre and postnatal morphine exposure: exposure-induced effects and sex differences in the behavioural
Julia Timár1, Melinda Sobor, Kornél P Király
1Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary. timjul@pharma.sote.hu
Insights
Maternal morphine (MO) exposure during pregnancy or after birth can lead to long-term behavioral changes in offspring. Prenatal MO exposure particularly increases vulnerability to drug abuse in adulthood.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Opioid exposure during sensitive developmental periods can have lasting effects.
- Understanding the long-term consequences of perinatal opioid exposure is crucial for public health.
- Morphine (MO) exposure can impact neurodevelopment and behavior.
Purpose of the Study:
- To investigate the long-term behavioral effects of perinatal morphine exposure in rats.
- To examine sex differences in the behavioral consequences of morphine exposure.
- To assess the impact of prenatal versus postnatal morphine exposure on offspring behavior.
Main Methods:
- Rats were exposed to morphine (5-10 mg/kg/day) or saline from gestational day 1.
- Behavioral assessments included habituation to a novel environment, antinociception, and conditioned place preference.
- Offspring were tested at different life stages: post-weaning, adolescence, and adulthood.
Main Results:
- Male offspring exposed to morphine showed delayed habituation and reduced antinociceptive sensitivity.
- Morphine-induced place preference was enhanced in exposed adults, particularly females.
- Prenatal morphine exposure induced more significant changes than postnatal exposure.
Conclusions:
- Perinatal morphine exposure, even at moderate doses, causes long-term behavioral alterations in offspring.
- Offspring exposed to morphine may exhibit increased vulnerability to drug abuse in adulthood.
- Developmental stage and sex influence the long-term behavioral consequences of morphine exposure.
Abstract:
This study investigated the behavioural consequences of peri, pre and postnatal morphine (MO) exposure in rats. From gestational day 1 dams were treated with either saline or MO subcutaneously once a day (5 mg/kg on the first 2 days, 10 mg/kg subsequently). Spontaneous locomotor activity in a new environment (habituation) and antinociceptive effects of MO were measured separately in male and female pups after weaning and also in late adolescence or adulthood. The rewarding effect of MO was assessed by conditioned place preference in adult animals. Both exposure-induced and sex differences were observed. A significant delay in habituation to a new environment and decreased sensitivity to the antinociceptive effect of MO were found in male offspring of MO-treated dams. In contrast, the place preference induced by MO was enhanced in the MO-exposed adult animals and this effect was more marked in females. Prenatal exposure to MO resulted in more marked changes than the postnatal exposure through maternal milk. The results indicate that a medium MO dose administered once-daily results in long-term consequences in offspring and may make them more vulnerable to MO abuse in adulthood.
