Transgenerational influence of parental morphine exposure on pain perception of the male and female offspring

Hamid Ahmadian moghadam,1,* Mitra-sadat sadat-shirazi,2 Zahra kheiri,3 Ardeshir akbarabadi,4 Heidar toolee,5 Mohammad-reza zarrindast ,6

1. Department of Genetics, Iranian National Center for Addiction Studies, Tehran University of Medical Sciences
2. Department of Genetics, Iranian National Center for Addiction Studies, Tehran University of Medical Sciences
3. Department of Genetics, Iranian National Center for Addiction Studies, Tehran University of Medical Sciences
4. Department of Veterinary Medicine, Garmsar Branch, Islamic Azad University
5. Department of Anatomy, School of Medicine, Tehran University of Medical Sciences
6. Department of Genetics, Iranian National Center for Addiction Studies, Tehran University of Medical Sciences

Abstract


Introduction

The social differences in drug use and consumption patterns vary from different time periods and between countries suggesting a large environmental component. several evidence showed that drug addiction has strong genetic component and it has link to environmental variables. the studies suggest that addiction has predicted heritability in range of 30 to 70 percent furthermore, the effect of parental drug-exposure before gestation on behavioral state of offspring has been little studied. the main objective of the study is to measure the influence of parental morphine exposure on pain perception of the male and female offspring.

Methods

Adult male and female wistar rats received morphine for 21 consecutive days. moreover, the offspring of animals with different parental morphine-exposure were divided into four distinct groups including offspring of healthy parents (ctl), offspring of morphine-abstinent female and healthy male rats (mma), offspring of morphine-abstinent male and healthy female rats (pma) and offspring of morphine-abstinent male and female rats (bma). pain perception were quantified in the offspring. the acute and persistent pain were quantified thought formalin test. visceral pain were induced through writhing test by injection of acetic acid and acute thermal pain was induced by hot plate test.

Results

The results revealed that the male offspring with mma, pma and bma parents, the total time of writhing and total number of writhing significantly were reduced. the results showed that tolerance for perception of acute pain in male offspring with pma, mma and bma parents significantly reduced. results showed male offspring in control group had higher tolerance for perception of acute pain in comparison with females. moreover, the lowest perception of persistent pain was observed in male offspring with bma parents. the results revealed that there is no significant difference between offspring for acute thermal pain.

Conclusion

Results revealed the equal role of each parent in epigenetic inheritance of pain perception. however, variance analysis signified the important role of maternal epigenetic inheritance.

Keywords

Transgenerational influence, morphine exposure, pain perception, offspring