The long-term effects of neonatal surgical pain and analgesic exposure on pain perception and ethanol preference in mice

Abstract

Many studies show that neonatal exposure to pain and/or morphine alter adult pain sensitivity in humans and rodents. Some studies also found that such neonatal treatments affected ethanol preference in rats. The current study examined the long-term effects of neonatal exposure to surgical pain and/or morphine on pain behaviors and alcohol preference in mice. Adult pain behaviors were measured with three tests, the tail flick (TF), hot plate (HP), and abdominal constriction (AC) tests, and all the tests indicated that pain exposure decreased the sensitivity to noxious stimuli in adulthood. Neonatal morphine exposure did not have any effects when injected alone but reversed the effects of pain when injected after the surgery. We also observed a sex difference in pain response. Neither pain nor morphine exposure affected ethanol preference