Biomedical subjects

J Sarker

Publications and source records attributed to J Sarker.

2 recordsLinked to original sources

PubMed1992

Effects of transections to the vomeronasal nerves or to the main olfactory bulbs on the initiation and long-term retention of maternal behavior in primiparous rats.

While the onset of maternal behavior at parturition is mediated by hormones, the maintenance of maternal behavior during the first few postpartum weeks depends on experiences acquired while the dam interacts with pups (Rosenblatt, 1990). In fact, if female rats are permitted as little as 2 h or maternal experience within 36 h after Cesarean delivery, they exhibit heightened maternal behavior during maternal induction tests 10 days later; in contrast, dams separated from young at the time of Cesarean delivery and not permitted a maternal experience fail to respond maternally in tests 10 days later (Orpen & Fleming, 1987). In this study we investigated the role of chemosensory input through the vomeronasal and main olfactory systems in this maternal experience effect. Six groups of primiparous females were tested for maternal behavior to foster pups presented 9-10 days after Cesarean delivery: three groups were permitted to interact with pups for a 2-h period 36 h after Cesarean delivery; and three groups were separated from pups until testing and were given no maternal experience. Within each experience condition, one group sustained bilateral section of the vomeronasal nerves, one sustained bilateral coronal cuts through the midsection of the main olfactory bulbs, and one group sustained small medial olfactory bulb cuts. The results showed that animals sustaining vomeronasal or olfactory transections, regardless of experience condition, exhibited significantly reduced latencies to maternal behavior in maternal induction tests. However, these chemosensory disruptions did not prevent an additional facilitation of maternal behavior produced by a prior maternal experience.

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PubMed1990

Experience-hormone interactions and maternal behavior in rats.

Three studies were conducted to determine the effects of reproductive condition and hormonal background on the acquisition and retention of a prior maternal experience. In the first study five experience conditions were compared. All animals gave birth and received either no postpartum contact with pups or 1/2 hr, 1 hr, 2 hr or 24 hr of pup contact and were tested for maternal behavior 10 days later. Animals receiving pregnancy and parturitional experience, but minimal social experience with young, exhibited significantly longer maternal onset latencies than did groups receiving 2 or 24 hr of prior experience; also, comparisons of 10- and 30-day retention intervals indicated that animals tested 10 days after a 24-hr experience exhibited shorter latencies than those tested 30 days later. Thus, the duration of the postpartum experience and the interval since prior experience both affect the level of maternal responsiveness shown. In the second study six groups of females were tested. Four groups were permitted one day of interaction with pups either after parturition (primiparous animals) or following pup induction procedures (nulliparous animals) and were tested for their maternal responsiveness to foster pups 25-35 days later, either on day 19 of a subsequent pregnancy or following resumption of estrous cycling. For most measures of maternal behavior there were significant main experience and test effects; experienced and pregnant animals exhibited shorter latencies to retrieve, lick and crouch over pups than did inexperienced and cycling animals, respectively. Significant interactions were also found for genital licking latency as well as for retrieval and crouch frequencies.(ABSTRACT TRUNCATED AT 250 WORDS)

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