Reproductive experience influences grooming behavior during pregnancy in rats

Abstract

The pregnancy-induced increase in self-licking observed in rats is important for mammary gland development and lactation. Reproductive experience has epidemiologial implications such as a decrease in the incidence of mammary gland cancer in women and it also influences various behavioral, neurochemical and endocrine parameters. The aim of the present study was to investigate the influence of reproductive experience on grooming behavior patterns during pregnancy in rats. Self-grooming behavior was measured in age-matched virgin, primi-and multigravid (days 7, 8, 9, 19, and 20 of pregnancy) rats. General grooming (head, forelimbs and shoulders) was not significantly different among virgin, primi-and multigravid rats during pregnancy. Confirming previous work, pregnant rats spent significantly more time in specific grooming (mammary glands, nipple lines, genital and pelvic regions) than did virgin animals. In addition, selflicking of mammary glands was significantly increased in multi-as compared to primigravid rats on days 8, 9, 19 and 20 of pregnancy. The increase in mammary gland grooming observed in multigravid rats appears to be a consequence of previous reproductive experience. These data show that reproductive experience modulates mammary gland grooming during pregnancy, possibly contributing to successful reproduction.

Orientation of newborn mice to lactating females: Identifying biological substrates of semiochemical interest

“…Evidence for such lactationrelated functional changes is scarce in the mouse, but homologous phenomena in other mammals indicate higher attractiveness of abdominal odor (rabbit: Hudson, Gonzàlez-Mariscal, & Beyer, 1990), or elevated excretion rate of sebum (women: Burton, Shuster, Cartlidge, Libman, & Martell, 1975). Self-licking of the abdomen and nipple-line by females increases during late pregnancy and lactation (mice: Harvey & Mann, 1987;rats: Roth & Rosenblatt, 1967;Serafim & Felicio, 2002). In the mouse, the nipples are altered in size and surface microstructure during the first days of lactation (Toyoshima et al, 1998), and the number and size of nipple's sebaceous glands increase on Day 17 of gestation and remain elevated up to Day 18 of lactation, indicating increased sebum excretion (Koizumi, Horiguchi, Tomita, Kato, & Harigaya, 2003).…”

“…Beside such local effects mediated by mammary exocrine structures, behavior also participates in shaping the chemosensory properties of the females' abdomen and nipples. Self-licking of the abdomen and nipple-line by females increases during late pregnancy and lactation (mice: Harvey & Mann, 1987;rats: Roth & Rosenblatt, 1967;Serafim & Felicio, 2002). Additionally, self-licking or licking of pups may contribute to spread ventrally either the females' own facial, anogenital and urinary substrates, or substrates emitted by pups (e.g., amniotic fluid, urinary/fecal substrates).…”

Reproductive experience modifies dopaminergic function, serum levels of prolactin, and macrophage activity in female rats

“…It can be described as a rich social and hormonal experience, beginning with male interaction and mating, then pregnancy and delivery and ultimately, lactation, pup relationship and weaning (Hucke et al, 2001;Serafim and Felicio, 2002).…”

Hormonal influences on neuroimmune responses in the CNS of females

“…It can be described as a rich social and hormonal experience that begins by interacting and mating with a male, followed by pregnancy, parturition, and ultimately lactation, interaction with pups, and weaning (Mann and Bridges, 2001; Serafim and Felicio, 2002). Striking behavioral and neuroendocrine alterations due to motherhood have been reported in several mammalian species including mice, rats, rabbits, sheep, and humans.…”