Postpartum Females Research Articles

Heterotrimeric G proteins of the Gq/11 family are crucial for the induction of maternal behavior in mice.

Heterotrimeric G proteins of the G(q/11) family transduce signals from a variety of neurotransmitter receptors and have therefore been implicated in several functions of the central nervous system. To investigate the potential role of G(q/11) signaling in behavior, we generated mice which lack the alpha-subunits of the two main members of the G(q/11) family, Galpha(q) and Galpha(11), selectively in the forebrain. We show here that forebrain Galpha(q/11)-deficient females do not display any maternal behavior such as nest building, pup retrieving, crouching, or nursing. However, olfaction, motor behavior and mammary gland function are normal in forebrain Galpha(q/11)-deficient females. We used c-fos immunohistochemistry to investigate pup-induced neuronal activation in different forebrain regions and found a significant reduction in the medial preoptic area, the bed nucleus of stria terminalis, and the lateral septum both in postpartum females and in virgin females after foster pup exposure. Pituitary function, especially prolactin release, was normal in forebrain Galpha(q/11)-deficient females, and activation of oxytocin receptor-positive neurons in the hypothalamus did not differ between genotypes. Our findings show that G(q/11) signaling is indispensable to the neuronal circuit that connects the perception of pup-related stimuli to the initiation of maternal behavior and that this defect cannot be attributed to either reduced systemic prolactin levels or impaired activation of oxytocin receptor-positive neurons of the hypothalamus.

WING MORPHOLOGY AND FLIGHT PERFORMANCE IN ROUSETTUS LESCHENAULTI

We studied development of wings of Leschenault’s rousette, Rousettus leschenaulti. Wingspan and wing area grows linearly until 45 days of age. Young bats begin to flutter at 45 days, manage sustained flight at 60 days, and achieve independent foraging flight at 75 days. Aspect ratio varies until 15 days, and adult proportions are attained at 2 months. Wing loading decreases linearly until 50 days and thereafter increases slowly, possibly because of completion of growth of wing area. Wingspan growth fits a logistic model, whereas wing area growth fits a Gompertz model. Minimum predicted flight power (Pmp) and maximum range power (Pmr) begin to increase linearly after remaining relatively constant for 30 days. At 150 days both are nearly equal to 65% of the power requirements of postpartum females. The predicted minimum power speed (Vmp), maximum range speed (Vmr), and minimum theoretical radius of a banked turn (rmin) decrease for 40 days, thereafter increase linearly, and at 150 days all are close to 90% of the respective values of the postpartum females.

Reproductive biology of Carcharhinus acronotus in the coastal waters of South Carolina

The reproductive biology of blacknose sharks Carcharhinus acronotus in the western North Atlantic Ocean was studied by examining specimens collected in the coastal waters of South Carolina. Males begin the maturation process between 875 and 910 mm fork length (LF), as indicated by the presence of functional claspers and siphon sacs. The presence of vitellogenic oocytes and developing oviducal glands and uteri indicated that females begin to mature at c. 870 mm LF. Length at which 50% of the population reached maturity was 896 and 964 mm LF, equivalent to 4·3 and 4·5 years, for males and females, respectively. Gonado‐somatic indices suggested that spermatogenesis and vitellogenesis began after December. Mating took place during the end of May and the beginning of June. Fertilization occurred during late June and early July, suggesting that female blacknose sharks were capable of sperm storage. Based on the timing of fertilization and occurrence of females carrying near‐term pups in late May and early June, the gestation period for blacknose sharks was c. 11 months. Female blacknose sharks reproduced biennially based on the absence of vitellogenic oocytes in near‐term females and there being no indication of vitellogenesis in postpartum females. Male blacknose sharks were capable of reproducing annually as indicated by turgid genital ducts, which were observed in all mature males collected during late May and early June.

Maternal behavior: activation of the central oxytocin receptor system in parturient rats?

Parturition plays a critical role in the full expression of maternal behavior in postpartum females, yet the precise mechanism remains unclear. Here we examined the role of parturition in the activation of Fos and FosB in the central oxytocin receptor (OTR) system in rats. Although expression of FosB, not Fos, was seen in the piriform cortex (Pir) and caudate putamen of virgin and pregnant females, activation of Fos and FosB with extensive co-localization was found in the medial preoptic area, the bed nucleus of the stria terminalis and Pir of parturient brain. This parturition induced activation of Fos and FosB was identified in the central OTR-expressing cells as well as in oxytocinergic neurons. Our data provide direct evidence, for the first time, that parturition activates Fos and FosB in the central OTR system. We propose that Fos and FosB may have comparable functions on initiating maternal behavior at parturition.

Postpartum changes in the GABAergic system in the bed nucleus of the accessory olfactory tract

The bed nucleus of the accessory olfactory tract (BAOT) is a sexually dimorphic structure which controls the inhibition/disinhibition of the medial preoptic area in the expression of maternal behavior. Therefore, in the present study we investigated sex differences and the modulation of gamma-aminobutiric-acid (GABA) in the BAOT during the first two postpartum days. Four groups of Wistar rats: control males, control females, 0 h postpartum females and 48 h postpartum females, were used in this experiment. Sex differences in glutamate decarboxylase (GAD) and GABA A α-chain receptor densities were apparent in the BAOT. The hormonal and behavioral postpartum state affects GABAergic activity in the females’ BAOT in two ways: firstly, pregnancy and the first two postpartum days induce an increase in GABA A-receptor and GAD densities; secondly, the intensity of these activities are greater in the left hemisphere than in the right. These changes might be related to the BAOT’s function of inhibiting/disinhibiting maternal behavior.

Postnatal Development in the Indian Short-Nosed Fruit BatCynopterus sphinx: Growth Rate and Age Estimation

We studied the patterns of postnatal growth and changes in length of forearm, body mass and total epiphyseal gap in the captive free-flying short-nosed fruit bat Cynopterus sphinx. At birth young were altricial. By day five, their eyes had opened, and the pinnae become unfolded between sixth and ninth day of age. At the age of three days, the mean forearm length and body mass were equivalent to 42.2% and 18.2%, respectively of the values of postpartum females. The length of forearm increased linearly until 36 days and attained 94.1% of mean forearm length of postpartum females at the age of 219 days. Body mass of pups increased linearly until 60 days and attained 72.7% of mean mass of postpartum females at the age of 219 days. The length of total epiphyseal gap of fourth metacarpal-phalangeal joint increased until 15 days of age and subsequently decreased linearly, and closed at about 60 days of age. The age predicting equation based on the length of forearm is valid when its dimensions are between 29.4 mm and 52.4 mm (3–36 days of age). Similar equation but based on the length of total epiphyseal gap is valid when its dimensions range from 47.0 µm to 6.0 µm (15–60 days of age). Growth patterns of forearm length and body mass were best described by the logistic and Gompertz nonlinear growth models, respectively. There was no significant difference in the growth patterns of body mass and length of total epiphyseal gap with reference to lengths of forearm of captive and wild-grown pups.

Female preference for large males in sailfin mollies, Poecilia latipinna : the importance of predation pressure and reproductive status

We examined the effect of predation risk on female association patterns in the live-bearing sailfin molly (Poecilia latipinna). We tested two classes of females, with and without the risk of predation by a green sunfish (Lepomis cyanellus): (1) postpartum females (maintained with males until visibly gravid, then isolated and tested within 24-48 h of dropping a brood); and (2) non-postpartum females (different females, isolated from males for >50 days). When there was no apparent risk of predation, postpartum females showed a significant preference for large over small males, whereas non- postpartum females showed no size preference at all. When there was an apparent risk of predation, postpartum females maintained their preference for larger males and non-postpartum females continued to show no preference for large or small males. These results suggest that reproductive status (receptivity) plays a greater role in mate preference than predation risk. For postpartum females, the cost of not choosing a preferred mate may outweigh the potential cost of predation. Non-postpartum females either do not benefit from mating or are being indecisive about mating and thus are less likely to be choosy whether or not a predator is present.

Obsessional thoughts in postpartum females and their partners: Content, severity, and relationship with depression

Only a few studies have examined the development or exacerbation of obsessive–compulsive disorder (OCD) during pregnancy and the postpartum. Although the available literature suggests that OCD symptoms, particularly obsessional problems, develop at higher than expected rates among postpartum females, the overall prevalence of such symptoms in the postpartum remains unknown. Previous findings also suggest that intrusive distressing thoughts related to situational stressors are common in the general population. Therefore, the present study was designed to assess the presence and phenomenology of postpartum obsessive-like intrusive thoughts, images, and impulses in a large sample of parents with very young infants. Surveys were mailed to 300 childbearing women and their partners. Results were obtained from approximately one fifth of the sample; and 65% of respondents indicated the presence of obsessional intrusive thoughts. Intrusions were similar to “normal obsessions” as reported in previous research. Results are discussed in terms of the content of intrusive thoughts, their relationship to depression, and implications for etiological models of OCD and perinatal education.

Mating behaviour of bank voles (Clethrionomys glareolus) modified by hormonal and social factors

Summary The bank vole is a common European rodent. In a natural population the adult females are territorial, and during the breeding season each female's home range overlaps with the home range of several males. The aim of the present study was to investigate the influence of sexual experiences of females and males on mating behaviour. The results indicate that the activity of the female was modified by her sexual experience and by the experience of the partner. Females were more active in presence of sexually non-experienced than experienced males. Males also showed higher activity in the presence of virgin than in the presence of experienced females. Females in postpartum estrus were more active than virgins and injection of gonadotropins stimulated virgin females. Males tested with gonadotropin-treated virgin females or postpartum estrous females showed similar sexual activity. Sexual experience increased the activity of males; they approached receptive females frequently and exhibited a higher number of mountings than did non-experienced males. The higher activity of an experienced partner can prevent copulation with another male during the same estrus, so that only one male becomes the father of the offspring. The present results indicate that in sexually experienced males bulbectomy but not vomeronasalectomy decreased the sexual activity and only 2 out of 6 lesioned males copulated with receptive females.

Postnatal growth, age estimation and development of foraging behaviour in the fulvous fruit bat Rousettus leschenaulti.

This study documents the postnatal growth, age estimation and development of the foraging behaviour of the fulvous fruit bat Rousettus leschenaulti under captive conditions. At birth, the young were naked and pink with closed eyes and folded pinnae. By day four of age, their eyes had opened and the pups began to move. The mean length of forearm in 5-day-old pups was 24.9 mm and body mass was 10.8 g, equivalent to 32.3% and 14.2% of the values from postpartum females. The length of forearm and body mass increased linearly until 45 and 50 days, respectively, and thereafter maintained an apparent stability. The epiphyseal gap of the fourth metacarpal-phalangeal joint increased until 15 days, then decreased linearly until 75 days and thereafter closed. Age was estimated quantitatively, based on linear changes observed in the length of the forearm and epiphyseal gap. Pups began to roost separately, but adjacent to their mothers when 30 days old and flew clumsily when they were about 40 days old. After attaining clumsy flight, the young bats made independent foraging attempts feebly by biting and licking small fruit pieces. Young bats were engaged in suckling as well as ingesting fruits when they were about 50 days old. Between 55 and 65 days, they flew well and fed on fruits. At the age of 75 days, the young bats were completely weaned and at two months, their foraging behaviour was similar to that of their mothers. There was no significant difference in the growth pattern of the young maintained in captivity compared with those under natural conditions.

Four new species of Eisothistos (Anthuridea: Isopoda) from tubes of Spirorbidae (Serpuloidea: Polychaeta)

Most were slim and <2 mm long. Eisothistos macrurus Wägele, with a cluster of large dorsal setae on heads and anterior pereon of post-partum females, broods in Mediterranean spirorbid tubes. It has one pair of hind telson plumose setae, each with a small companion seta arising from the same marginal notch, separated from each other by four, five or six marginal teeth. Anterior to the hind margin (by a distance ca 0.2 of telson width) two small setae may arise dorsally from the telson in adcentral positions (about the same distance apart as plumose setae). Its ‘sibling’ relatives, Eisothistos adcentralis sp. nov. from North-West Atlantic and Eisothistos adlateralis sp. nov. from New Zealand, have two small dorsal setae (anterior to hind margin) near the mid-line in the former and close to the sides of the telson in latter, with only two marginal teeth between setae of the plumose pair. Other southern forms also have adlateral dorsal setae. Eisothistos poseidon sp. nov. from Australia has each uropodal ramus like a trident. Eisothistos bifidus sp. nov. from Cape Town has hind telson plumose setae separated by a single bifid tooth. The collections included many juveniles and more than 30 gravid or caring females, but only three males, two of E. poseidon and one of E. adcentralis, with a specimen of doubtful sex, probably a senescent female of E. bifidus.

Observations on Neonatal Aggregations and Associated Behaviors in the Prairie Rattlesnake, Crotalus viridis viridis

In August and September of 1991 we observed three groups of neonatal prairie rattlesnakes (Crotalus viridis viridis) near a prairie dog town in the Sand Hills (Cherry County, Nebraska). One of these groups included at least 31 neonates and 2 postpartum females. In addition to spatio-temporal association of neonates and putative mothers, we observed a radio-tagged male prairie rattlesnake consecutively visit two natal sites, just before and just after parturition. Mean mass of neonates in two groups was below the range previously reported for this subspecies. Young-of-the-year (YOY) captured during ingress were longer and weighed more than neonates captured at birth. Feces collected from nine YOY captured at hibernacula contained pocket mouse (Perognathus spp.) remains. In contrast to other intensively studied populations, most YOY in the Sand Hills appear to feed and grow before first hibernation.

Lymphocytic infundibulo- neurohypophysitis with hypothalamic and opticpathway involvement: report of a case and review of the literature

BACKGROUND Lymphocytic adenohypohysitis and lymphocytic infundibulo-neurohypophysitis are rare auto-immune mediated diseases of the anterior and posterior pituitary, respectively. The former usually manifests as insufficiency of anterior pituitary hormone secretion, associated in many patients with disturbances of vision. The latter presents as diabetes insipidus of central origin. They present most commonly in pregnant or postpartum females. There have been infrequent reports in females with no association with pregnancy, and in males. CASE DESCRIPTION We present a nulliparous female with central diabetes insipidus, pan-hypopituitarism, and severely impaired vision. Magnetic resonance imaging demonstrated a large mass involving the hypothalamus, infundibulum, optic nerves, chiasm, and tracts. At operation, the optic pathways were found to be grossly involved in the inflammatory mass. Histological examination of a biopsy demonstrated a nonspecific, mixed inflammatory infiltrate, composed predominantly of lymphocytes and plasma cells. She responded dramatically to treatment with dexamethasone, with disappearance of the mass on serial imaging studies and improvement in vision. In addition, she received hormone replacement therapy. CONCLUSION We present a case of lymphocytic infundibulo-neurohypophysitis unique in the degree of optic pathway inflammatory involvement, with a documented response to steroids.

Delayed ovulation and parturition in a viviparous alpine lizard (Niveoscincus microlepidotus): morphological data and plasma steroid concentrations.

The southern snow skink, Niveoscincus microlepidotus, exhibits an unusual biennial reproductive cycle with an extended gestation period of approximately 1 year. Morphological data were gathered on a monthly basis, providing a detailed picture of the reproductive cycle. Vitellogenesis begins in spring, immediately after parturition. Maximum follicular diameter is reached before the winter hibernation period and ovulation occurs the following spring. Embryos are fully developed and reach maximum size by early autumn. Yolk reserves are depleted before winter. Birth of between one and four young occurs the following spring. Plasma progesterone concentrations are low (2.7 +/- 0.9 ng mL(-1)) in post-partum females, begin to rise in autumn in vitellogenic females and peak (38.5 +/- 7.9 ng mL(-1)) in pre-ovulatory females after hibernation. Concentrations are high (15.4 +/- 5.9 ng mL(-1)) in early pregnancy and decline to basal levels before winter and well before birth in spring. Plasma oestradiol concentrations peak during vitellogenesis (1.0 +/- 0.3 ng mL(-1)) and decline to basal levels during pregnancy (0.2 +/- 0.03 ng mL(-1)). A second oestradiol peak occurs before parturition (0.7 +/- 0.2 ng mL(-1)). Thus, functional completion of vitellogenesis and gestation is achieved by autumn in successive years. The mechanisms that defer ovulation and parturition by a further six months are unknown.

Effect of nitric oxide synthase inhibition on fos expression in the hypothalamus of female rats following central oxytocin and systemic urethane administration.

Three experiments were carried out to investigate the pattern of neuronal activation induced by central oxytocin administration and its modulation by nitric oxide (NO). First, we compared the induction of Fos-like immunoreactivity (lir) in the supraoptic (SON) and paraventricular (PVN) nuclei and medial preoptic area (MPOA) after central oxytocin administration between nonlactating and lactating rats. Next, we investigated whether NO modulated Fos induction following central oxytocin administration using a nitric oxide synthase (NOS) inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME). Finally, to determine whether the effects of NOS inhibition on Fos induction would generalize to stimuli other than oxytocin, we compared Fos-lir in the SON and PVN of lactating and nonlactating rats following L-NAME and urethane administration. In the first two experiments, oxytocin (50 ng in 2 microl) or vehicle was administered into the third ventricle. L-NAME (50 mg/kg) was given by an intraperitoneal (i.p.) injection 30 min before oxytocin administration (experiment 2) or an i.p. injection of urethane (1.4 g/kg) (experiment 3). In all experiments, lactating rats were tested on day 12 or 13 postpartum and nonlactating females at least 11 days after surgery or the start of the experiment. Central oxytocin infusion induced Fos expression in the SON and PVN in lactating and nonlactating rats and in the MPOA and bed nucleus of the stria terminalis in lactating rats. Overall, lactating rats that received L-NAME and oxytocin had a greater number of cells showing Fos-lir in both the SON and PVN. Conversely, L-NAME administration reduced Fos-lir in the SON and PVN in oxytocin-stimulated nonlactating rats. In urethane-treated rats, L-NAME administration did not change Fos-lir in lactating rats but reduced Fos-lir in nonlactating rats. These data suggest that the role of NO in modulating the activity of neurones in discrete nuclei in the hypothalamus varies across reproductive state and with the stimulus presented.

Reproduction in Northern Populations of the Ridgenose Rattlesnake,Crotalus willardi(Serpentes: Viperidae)

Abstract We describe the reproductive biology of northern populations of Crotalus willardi using data gathered from four long-term field studies, histological examination of museum specimens, and literature records. Spermiogenesis occurs summer to early autumn. All male C. willardi examined contained sperm in the vas deferens (June–September) and had enlarged kidney sexual segments (June–October). Parturition occurs from late July through August (n = 17). Postpartum females appear to remain reproductively inactive prior to hibernation. Secondary yolk deposition (vitellogenesis) commences in the late spring or early summer, one or more years after parturition. Ovulation and fertilization probably occur early in the spring, followed by 4–5 months gestation. Copulation occurs in midsummer to early fall (n = 10). Repeated observations of marked females over several years, proportion of adult gravid females (60% Crotalus willardi obscurus, 40% Crotalus willardi willardi, 51% pooled), observations on captive an...

Age and Experience Affect Female Choice in the Guppy (Poecilia reticulata)

Female choices of males, and how these choices are influenced by ecological and social factors, have been studied extensively. However, little is known about the effects of age and breeding experience on female mating decisions. We used video techniques to examine female mate choice in guppies based on the area of carotenoid (orange) pigmentation on the body. Females were presented with paired images of males, one ornamented and the other plain. Visual preference for each male was measured. Age-related changes in the criteria of choice were examined by comparing the responses of the same mature but sexually inexperienced 6-mo-old and 12-mo-old females. Effects of breeding experience on female choice were examined by comparing mate preferences of 12-mo-old female virgins with their preferences after they had mated and produced a brood. Female preferences for ornamented males with large areas of carotenoid pigment changed with age but not with mating experience. Six-month-old virgin females preferred ornamented males, whereas 12-mo-old virgin and postpartum females did not differentiate between males based on orange coloration. The results are discussed in light of life-history theory and have important implications for studies of sexual selection as well as for the design of mate-choice studies.

Age and Experience Affect Female Choice in the Guppy (Poecilia reticulata)

Female choices of males, and how these choices are influenced by ecological and social factors, have been studied extensively. However, little is known about the effects of age and breeding experience on female mating decisions. We used video techniques to examine female mate choice in guppies based on the area of carotenoid (orange) pigmentation on the body. Females were presented with paired images of males, one ornamented and the other plain. Visual preference for each male was measured. Age‐related changes in the criteria of choice were examined by comparing the responses of the same mature but sexually inexperienced 6‐mo‐old and 12‐mo‐old females. Effects of breeding experience on female choice were examined by comparing mate preferences of 12‐mo‐old female virgins with their preferences after they had mated and produced a brood. Female preferences for ornamented males with large areas of carotenoid pigment changed with age but not with mating experience. Six‐month‐old virgin females preferred ornamented males, whereas 12‐mo‐old virgin and postpartum females did not differentiate between males based on orange coloration. The results are discussed in light of life‐history theory and have important implications for studies of sexual selection as well as for the design of mate‐choice studies.

Opioid receptor antagonism during early lactation results in the increased duration of nursing bouts

High levels of μ opioid receptor activation during the postpartum period result in the disruption of ongoing maternal behavior. The role of physiological levels of endogenous opioids on the mediation of maternal behavior in postpartum females, however, has not been closely examined. The purpose of the present experiments was to examine the function of endogenous opioids during early and mid-lactation by treating postpartum females with the opioid antagonist naloxone and monitoring their behavioral interactions with pups. Although this treatment did not lead to any qualitative differences in the maternal behaviors measured (pup retrieval and grooming, nest building, grouping of pups, or crouching over pups), there was a quantitative difference in the amount of time the females spent with pups on the nest and actively nursing pups. Naloxone, given either systemically or centrally (intracerebroventricularly), resulted in prolonged nursing and nesting bouts. This effect, however, was only observed during the early lactation time point (postpartum days 5–7). Females tested later in lactation (postpartum days 10–12 or 12–14) did not display the increased nursing or nesting bouts in response to the antagonist. These data indicate that central opioids play a role in the duration of nursing bouts during early lactation.

Comparison of the “Nursing” and Other Parental Behaviors of Nulliparous and Lactating Female Rats

Virgin female rats display maternal behaviors after continuous exposure to pups (sensitization) that are in some respects similar to those of postpartum females. We herein provide a detailed comparison of the “nursing” and other parental behaviors of maternally sensitized virgin females and postpartum lactating dams. Ovariectomized and intact virgin females were exposed to pups until displaying maternal behavior. On the females' fourth day of maternal responsiveness, the pups were removed for 3 h and then returned, and subject–litter interactions were observed for 45 min. Behavior of maternal virgins was compared with that of lactating dams observed on day 4 postpartum interacting with either suckling pups or pups unable to suckle due to perioral anesthesia. Ovariectomy had no effect on behavior of virgins. Retrieval and licking of pups were deficient in virgins compared with lactating dams. Suckled dams showed prolonged kyphosis (upright crouched nursing), whereas nonsuckled dams displayed little kyphosis but rather were often in a hunched position over pups. Some aspects of quiescent “nursing” behaviors of virgins were surprisingly similar to those of suckled dams, including the latency to and duration of quiescence. Nonsuckling pup stimulation elicited more kyphosis in virgins than in lactating dams, which was still much less than in suckled dams. Virgins also “nursed” pups in hunched and prone postures. Differences between sensitized and postpartum females in their maternal behaviors likely reflect differences in motivation as well as sensory inputs they receive from pups. In particular, sensory regulation of “nursing” behaviors is influenced by reproductive state because nonsuckling pups elicit different postural responses in sensitized and lactating mothers.