RESPONSE TO MATERNAL SEPARATION IN INFANT GUINEA-PIGS EXPOSED TO INTRAPARTUM MEPERIDINE

We investigated whether opiate analgesics as commonly administered to women during labor would affect later response to maternal separation in infant guinea pigs. Meperidine hydrochloride (10-15 mg/kg i.m.) was administered to late-pregnant guinea pigs 5 min prior to labor induct ion with oxytocin. On Day 11 or 12 postnatal, pup distress vocalizatio ns, locomotor activity, and plasma cortisol were measured under one of two conditions: alone (alone in a novel environment for 30 min) or mo ther (with the dam in the novel environment). Female pups exposed to i ntrapartum meperidine emitted fewer vocalizations than controls in the alone condition. Plasma cortisol was higher in meperidine females in the alone condition than in controls at the end of the separation peri od, but the difference was not significant. There was no drug effect o n vocalizations or cortisol in males. Neither test condition nor drug affected activity level. The data suggest that intrapartum opiates may alter separation-induced distress in female guinea pig infants. (C) 1 995 John Wiley and Sons, Inc.