Puerperal blockade of cholecystokinin (CCK1) receptors disrupts maternal behavior in lactating rats.

Blockade of cholecystokinin (CCK) receptors potentiates the morphine-induced disruption of maternal behavior. The present study was undertaken to determine whether treatment with lorglumide, a CCK1 antagonist during late pregnancy and early lactation can influence the maternal behavior during lactation. A possible influence of this treatment on general activity was also assessed. Twenty-seven female Wistar rats were pretreated with lorglumide (1.0mg/kg/day; sc) or saline for seven days, starting on the 17th d of pregnancy. After the withdrawal of this treatment, animals were acutely challenged with saline on day 5 and with morphine sulfate (3.0mg/kg; sc) on days 6,10, and 17 of lactation. Groups were pretreated with saline and challenged with saline (group SS) and morphine (group SM), pretreated with lorglumide and challenged with saline (group LS) and morphine (group LM). Animals were also tested for general activity on days 25 and 33 postpartum after an acute challenge with saline and morphine, respectively. Maternal behavior testing began 30 min after the acute injections at which time pups were placed throughout each mother's cage. Latencies for pup retrieval, grouping, crouching and for full maternal behavior responses were scored. Lorglumide pretreatment inhibited maternal behavior of LS vs SS group and potentiated the morphine-induced disruption of this behavior in all days of test (LM vs SM group). No significant differences were found in general activity on days 25 and 33 postpartum. These data suggest that blockade of CCK1 receptors during puerperal period has long-term implications for maternal behavior.