The role of lactogenic hormones in maternal behavior in female rats

Bridges, Robert S.

doi:10.1111/j.1651-2227.1994.tb13263.x

Cited by 59 publications

(30 citation statements)

References 52 publications

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“…Although current evidence suggests that only the mesolimbic dopamine system is affected by early experiences, it would be interesting to establish whether early experience also affects the hypothalamic dopamine system. Changes to the hypothalamic dopamine system may also affect the prolactin, since dopamine is a prolactin inhibitor (Kramer & Hopkins, 1982) and prolactin is an important hormone mediating the expression of maternal behavior (Bridges, 1994). Prolactin has also been related to the expression of maternal responsiveness during the juvenile period (Kinsley & Bridges, 1988).…”

Section: Early Separation and The Dopamine Systemmentioning

confidence: 99%

How early maternal separation and juvenile experience with pups affect maternal behavior and emotionality in adult postpartum rats

Rees

Fleming

2001

Animal Learning & Behavior

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To assess the effects of preweaning and juvenile experiences on adult maternal behavior, two experiments were completed. In Experiment 1, pups were separated for long periods or short periods or were left undisturbed over the 1st week. Following weaning, the rats were exposed to foster pups over a 5-day period or were left undisturbed. There were no effects of early experience on juvenile behavior. In adult postpartum maternal tests, short separations reduced latencies to express maternal behaviors, whereas long separations combined with juvenile exposure to pups increased latencies. In Experiment 2, pups were separated for long periods or were left undisturbed over the 1st week. Following weaning, the rats were exposed to foster pups for 4 days or 8 days or were left undisturbed. Long separation retarded maternal responding in juvenile animals but had no effect on the adults. Four days of juvenile experience had negative effects on adult behavior, whereas 8 days did not have an effect.

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Section: Early Separation and The Dopamine Systemmentioning

confidence: 99%

How early maternal separation and juvenile experience with pups affect maternal behavior and emotionality in adult postpartum rats

Rees

Fleming

2001

Animal Learning & Behavior

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“…For example, Mann & Bridges (2002) found the numbers of cells expressing PRL-R mRNA in the medial preoptic nuclei were significantly increased 2 h postpartum, but then declined back to pre-pregnancy levels throughout the remainder of lactation. The medial preoptic nucleus has been well characterized as a site of prolactin action to induce maternal behaviour in rats (Bridges 1994, Bridges et al 1997. During pregnancy, the lactogenic hormones are thought to prime the brain for maternal behaviour, so that at parturition there is an immediate onset of maternal responsiveness (Bridges et al 1996).…”

Section: Discussionmentioning

confidence: 99%

“…Prolactin has been implicated in the regulation of a variety of brain functions, including the suppression of adrenocorticotrophin secretion during the stress response (Torner et al 2001), an increase in feeding and appetite (Sauve & Woodside 1996, 2000, and the suppression of fertility (Cohen-Becker et al 1986), as well as the well-characterized short-loop negative feedback regulation of its own secretion by stimulating tuberoinfundibular dopamine (TIDA) neuronal activity (Freeman et al 2000). In addition, prolactin is known to be involved in further brain functions during lactation, such as the release of oxytocin for the milk ejection reflex (Parker et al 1991, Ghosh & Sladek 1995 and induction of maternal behaviour (Bridges 1994). The presence of PRL-R in the brain suggests a direct action of prolactin in the central nervous system (CNS) to regulate these functions.…”

Section: Introductionmentioning

confidence: 99%

Quantitation of prolactin receptor mRNA in the maternal rat brain during pregnancy and lactation

Augustine¹,

Kokay²,

Andrews³

et al. 2003

Journal of Molecular Endocrinology

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Prolactin receptor (PRL-R) expression in the brain is increased in lactating rats compared with non-pregnant animals. The aim of the present study was to determine the time-course of changes in PRL-R mRNA levels during pregnancy and/or lactation, and to determine relative levels of the two forms (short and/or long form) of receptor mRNA in specific brain regions. Brains were collected from female rats on dioestrus, days 7, 14 or 21 of pregnancy, day 7 of lactation or day 7 post-weaning. Frozen, coronal sections were cut (300 µm) and specific hypothalamic nuclei and the choroid plexus were microdissected using a punch technique. Total RNA was extracted and reverse transcribed, then first strand cDNA was amplified using quantitative real-time PCR. Results showed an up-regulation of long-form PRL-R mRNA in the choroid plexus by day 7 of pregnancy compared with dioestrus, which further increased on days 14 and 21 of pregnancy and day 7 of lactation, and then decreased to dioestrous levels on day 7 post-weaning. Short-form PRL-R mRNA levels increased on day 14 of pregnancy relative to dioestrus, increased further on day 7 of lactation and decreased on day 7 post-weaning. Changes in mRNA were reflected in increased levels of PRL-R immunoreactivity in the choroid plexus during pregnancy and lactation, compared with dioestrus. In the arcuate nucleus, long-form PRL-R mRNA was increased during pregnancy. In contrast to earlier work, no significant changes in short-or long-form PRL-R mRNA expression were detected in several other hypothalamic nuclei, suggesting that changes in hypothalamic mRNA levels may not be as marked as previously thought. The up-regulation of PRL-R mRNA and protein expression in the choroid plexus during pregnancy and lactation suggest a possible mechanism whereby increasing levels of peripheral prolactin during pregnancy may have access to the central nervous system. Together with expression of long-form PRL-R mRNA in specific hypothalamic nuclei, these results support a role for prolactin in regulating neuroendocrine and behavioural adaptations in the maternal brain.

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“…Many functions have been attributed to this hormone. PRL regulates gonadal functions (4) and behavior such as nest building and the retrieval of offspring (5), and it exerts multiple effects on the immune system (6). The best characterized role of prolactin, however, is its ability to induce lobuloalveolar growth in the mammary gland (7) and to stimulate postpartum lactogenesis.…”

Section: Prolactin and Its Receptormentioning

confidence: 99%