title: Long-term effects of neonatal surgery on adulthood pain behavior.
abstract: The long-term consequences of neonatal noxious stimulation on adulthood pain behavior were investigated in male and female mice. On the day of birth, mouse pups were exposed to a laparotomy under cold anesthesia followed by an analgesic dose of morphine (10 mg/kg) post-operatively, or a saline control. An additional group of subjects was exposed to the non-noxious aspects of the surgical procedure (cold exposure, separation from the dam, injection) comprising a 'sham' surgery control group, whereas another group of control subjects was administered an injection of saline or morphine, but was otherwise undisturbed. Behavioral observations of the pups immediately following the procedure indicated that the laparotomy produced increased distress vocalizations in the ultrasonic range (40 kHz) compared to both groups of control subjects. During 90 min observations periods following the surgery and 1-week later, maternal care did not vary among treatment conditions. In adulthood, offspring were tested for nociceptive sensitivity on the hot-plate (HP; 53 degrees C), tail-withdrawal (TW; 50 degrees C) and acetic acid abdominal constriction test (AC). On both the TW and the AC tests, neonatal surgery decreased pain behavior relative to both groups of control subjects, an effect that was reversed by post-operative morphine treatment. On the HP test, both groups of subjects exposed to the stressful aspects of neonatal surgery (laparotomy or sham surgery) exhibited decreased pain behavior in adulthood. These findings suggest that early exposure to noxious and/or stressful stimuli may induce long-lasting changes in pain behavior, perhaps mediated by alterations in the stress-axis and antinociceptive circuitry.
authors.affiliation: Department of Psychology, Haverford College, 370 Lancaster Avenue, Haverford, PA 19041, USA.
authors.forename: Wendy F
authors.initials: WF
authors.lastname: Sternberg
authors.forename: Laura
authors.initials: L
authors.lastname: Scorr
authors.forename: Lauren D
authors.initials: LD
authors.lastname: Smith
authors.forename: Caroline G
authors.initials: CG
authors.lastname: Ridgway
authors.forename: Molly
authors.initials: M
authors.lastname: Stout
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage; D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal / Q000502:physiology*; D005260:Female; D007813:Laparotomy / Q000379:methods; D008297:Male; D008425:Maternal Behavior / Q000187:drug effects / Q000502:physiology; D051379:Mice; D009020:Morphine / Q000008:administration & dosage; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology*; D010149:Postoperative Pain / Q000188:drug therapy / Q000503:physiopathology*; D011247:Pregnancy; D011930:Reaction Time; D013995:Time; D014828:Vocalization, Animal / Q000187:drug effects / Q000502:physiology
chemical_list: D000701:Analgesics, Opioid; D009020:Morphine