Neural and endocrine sensitivities to opioids decline as a function of multiparity in the rat

Mann, Phyllis E.; Bridges, Robert S.

doi:10.1016/0006-8993(92)90950-e

Cited by 86 publications

(55 citation statements)

References 59 publications

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“…During lactation, changes in gonadotropin levels were similar in primiparous and multiparous gerbils. Similar to rats, multiparous gerbils have attenuated sucklinginduced PRL secretion as compared to primiparous gerbils [16].…”

Section: Hormonal Variations During Different Reproductive States In mentioning

confidence: 92%

Variations in Serum Gonadotropin and Prolactin Levels during Consecutive Reproductive States in Mongolian Gerbils (Meriones unguiculatus)

Shi

2011

Exp. Anim.

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Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) levels were examined during consecutive reproductive states in Mongolian gerbils. The results indicate that FSH, LH, and PRL levels peak at proestrus, estrus, and diestrus, respectively. During early gestation in primiparous gerbils, gonadotropin levels were the lowest on day 6. This was followed by an increase in FSH and LH levels until days 18 and 15, respectively, with levels remaining constant until day 21. However, in multiparous gerbils, gonadotropin levels were the lowest on day 12 of gestation and were relatively stable between days 15 to 21. In both primiparous and multiparous gerbils, gonadotropin levels increased rapidly from day 21 of gestation to day 3 of lactation, and kept stable between 6-24 days of lactation. PRL peaked during early gestation on days 9 and 6 in the primiparous and multiparous gerbils, respectively, followed by a decline. PRL levels subsequently peaked again on day 21 before parturition. During lactation, PRL levels peaked on days 6 and 9 in primiparous and multiparous gerbils, respectively, followed by a decline until lactation ended. These findings suggest that variations in gonadotropin during the estrous cycle, gestation, and lactation in Mongolian gerbils are similar to those observed in rats, whereas prolactin levels differ. Changes in gonadotropin and prolactin levels during different reproductive states were found to be similar in primiparous and multiparous gerbils, and were correlated with the reproductive stages of Mongolian gerbils.

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Section: Hormonal Variations During Different Reproductive States In mentioning

confidence: 92%

Variations in Serum Gonadotropin and Prolactin Levels during Consecutive Reproductive States in Mongolian Gerbils (Meriones unguiculatus)

Shi

2011

Exp. Anim.

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“…Endogenous opioids have been shown to affect the rapid onset of maternal behavior at parturition in both a positive and negative fashion (Mann and Bridges, 1992;Mann et al, 1991;Rubin and Bridges, 1984;Thompson and Kristal, 1996). Central opioids can affect the onset and maintenance of maternal behavior.…”

Section: Introductionmentioning

confidence: 99%

“…The nature of this modulation depends on the site of action. Increased opioids in the medial preoptic area (MPOA) inhibit maternal responsiveness; the MPOA is an area widely accepted to be crucial for the mediation of maternal behavior (Mann and Bridges, 1992;Mann et al, 1991;Numan 2006;Rubin and Bridges, 1984). In contrast, morphine injected into the ventral tegmental area (VTA), which modulates motivation and reward, facilitates the onset of maternal behavior in virgin female rats and injection of the opioid antagonist naltrexone into the VTA disrupts the onset of maternal behavior in parturient female rats (Thompson and Kristal, 1996).…”

Section: Introductionmentioning

confidence: 99%

Ingestion of amniotic fluid enhances the facilitative effect of VTA morphine on the onset of maternal behavior in virgin rats

et al. 2009

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Previous research has shown that injection of morphine into the ventral tegmental area (VTA) facilitates the onset of maternal behavior in virgin female rats, and injection of the opioid antagonist naltrexone into the VTA disrupts the onset of maternal behavior in parturient rats. Placentophagia -ingestion of placenta and amniotic fluid, usually at parturition -modifies central opioid processes. Ingestion of the active substance in placenta and amniotic fluid, Placental Opioid-Enhancing Factor (POEF), enhances the hypoalgesic effect of centrally administered morphine, and more specifically, enhances δ-and κ-opioidreceptor-mediated hypoalgesia and attenuates μ-opioid-receptor-mediated hypoalgesia. POEF (in placenta or amniotic fluid) ingestion does not, by itself, produce hypoalgesia. In the present study, we tested the hypothesis that ingestion of amniotic fluid enhances the facilitative effect of opioid activity (unilateral morphine injection) in the VTA on the rate of onset of maternal behavior. Virgin female Long-Evans rats were given one intra-VTA injection of morphine sulfate (0.0, 0.01, or 0.03 μg, in saline) and an orogastric infusion of 0.25 ml amniotic fluid or saline once each day of the first three days of the 10-day testing period. Subjects were continuously exposed to foster pups that were replaced every 12 h; replacement of pups was followed by a 15-min observation period. Maternal behavior latency was determined by the first of two consecutive tests wherein the subject displayed pup retrieval, pup licking in the nest, and crouching over all foster pups, during the 15-min observation. We confirmed the previous finding that the VTA injection, alone, of 0.03 μg IntroductionRats at parturition show an almost immediate onset of appropriate maternal behavior. In contrast, the onset of maternal behavior in virgin rats that are continuously exposed to relatively constant-age foster pups (a procedure referred to as "concaveation", i.e., "with pups") is slow to appear, and is usually measured as the latency, in days, to the appearance of B R A I N R E S E A R C H 1 2 6 1 ( 2 0 0 9 ) 2 9 -3 6 ⁎ Corresponding author.

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“…In adult female mammals a reproductive experience, i.e., mating, pregnancy, parturition and lactation, has long-term behavioral, endocrine and neurochemical implications (1)(2)(3)(4)(5)(6). These influences have been demonstrated in various physiological states (7).…”

mentioning

confidence: 99%

“…Previous findings demonstrated that reproductive experience modulates a series of physiological and pharmacological responses (2-4,7-9). Other studies have indicated that multiparous female rats are also less sensitive to the opioid regulation of maternal behavior (2)(3)(4)15) and analgesia (2) than are primiparous females. Higher doses of opiates are needed to obtain a drug-induced disruption of maternal behavior in experienced animals.…”

mentioning

confidence: 99%

Reproductive experience influences grooming behavior during pregnancy in rats

Serafim

Felício

2002

Braz J Med Biol Res

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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.

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Neural and endocrine sensitivities to opioids decline as a function of multiparity in the rat

Cited by 86 publications

References 59 publications

Variations in Serum Gonadotropin and Prolactin Levels during Consecutive Reproductive States in Mongolian Gerbils (Meriones unguiculatus)

Variations in Serum Gonadotropin and Prolactin Levels during Consecutive Reproductive States in Mongolian Gerbils (Meriones unguiculatus)

Ingestion of amniotic fluid enhances the facilitative effect of VTA morphine on the onset of maternal behavior in virgin rats

Reproductive experience influences grooming behavior during pregnancy in rats

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