Home About us Contact
|
Home About us Contact | ||
|
|
||
Milk Ejection (milk + ejection)
Selected AbstractsNursing Synchronization and Milk Ejection Failure as Maternal Strategies to Reduce Allosuckling in Pair-Housed Sows (Sus scrofa domestica)ETHOLOGY, Issue 7 2005Gudrun Illmann Non-offspring nursing (allosuckling) is costly for lactating females. It is reasonable to assume, therefore, that mechanisms have evolved to control the frequency of allosuckling. It is suggested that the synchronization of nursing between females could be such a mechanism. The aim of this study was to investigate whether nursing synchronization is related to the timing of nursing behaviour of paired sows and the behaviour of alien piglets in relation to allosuckling. Specifically, we predicted that: (i) nursing synchronization will increase if there is a real risk of allosuckling compared with a situation where there is none, (ii) nursing synchronization indeed reduces allosuckling and, therefore, those nursings with allosuckling attempts will be less closely synchronized than those without allosuckling attempts and (iii) in non-synchronized nursings, the sows will more often employ another strategy to reduce allosuckling, namely, they will make the nursings non-nutritive by not releasing milk. Ten pairs of sows and their litters were used in this study. For each pair, the two sows were housed individually until their litters were weaned; however, their litters had access to both sows from day 11 post-partum. The behaviour of the 10 pairs of sows with their litters was videotaped for 6 h on days 10, 11, 17 and 24 post-partum. The frequency of allosuckling attempts, non-nutritive nursings and allosuckling during milk ejection was analysed for every pair for every day of observation. The observed frequency of nursing synchronization was high. The median interval between the start of a nursing within one pair of sows was 32 s. The first prediction was supported as synchronization became significantly tighter when piglets were given the possibility to allosuckle on day 11 [Cochran,Mantel,Haenszel (CMH) statistics, p < 0.0001]. The second prediction was also supported; the nursings were less closely synchronized when there were allosuckling attempts (CMH statistics, p < 0.05). Of all nursings, 36% had an allosuckling attempt; however, only 17% resulted in real allosuckling. Evidence in favour of the third prediction was also found as non-nutritive nursings were more frequent in non-synchronized nursings (CMH statistics, p < 0.05). Finally, real allosuckling during milk ejection was unrelated to the degree of nursing synchronization, as in less synchronized nursings, the sows responded to allosuckling attempts by not releasing milk. Our results suggest that sows are not able to completely suppress allosuckling; however, they can reduce its frequency through nursing synchronization and non-nutritive nursings. [source] Glutamatergic input governs periodicity and synchronization of bursting activity in oxytocin neurons in hypothalamic organotypic culturesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2003Jean-Marc Israel Abstract During suckling, oxytocin (OT) neurons display a bursting electrical activity, consisting of a brief burst of action potentials which is synchronized throughout the OT neuron population and which periodically occurs just before each milk ejection in the lactating rat. To investigate the basis of such synchronization, we performed simultaneous intracellular recordings from pairs of OT neurons identified retrospectively by intracellular fluorescent labelling and immunocytochemistry in organotypic slice cultures derived from postnatal rat hypothalamus. A spontaneous bursting activity was recorded in 65% of OT neurons; the remaining showed only a slow, irregular activity. Application of OT triggered bursts in nonbursting neurons and accelerated bursting activity in spontaneously bursting cells. These cultures included rare vasopressinergic neurons showing no bursting activity and no reaction to OT. Bursts occurred simultaneously in all pairs of bursting OT neurons but, as in vivo, there were differences in burst onset, amplitude and duration. Coordination of firing was not due to electrotonic coupling because depolarizing one neuron in a pair had no effect on the membrane potential of its partner and halothane and proprionate did not desynchronize activity. On the other hand, bursting activity was superimposed on volleys of excitatory postsynaptic potentials (EPSPs) which occurred simultaneously in pairs of neurons. EPSPs, and consequently action potentials, were reversibly blocked by the non-NMDA glutamatergic receptor antagonist CNQX. Taken together, these data, obtained from organotypic cultures, strongly suggest that a local hypothalamic network governs synchronization of bursting firing in OT neurons through synchronous afferent volleys of EPSPs originating from intrahypothalamic glutamatergic inputs. [source] Postpartum Maternal Oxytocin Release by Newborns: Effects of Infant Hand Massage and SuckingBIRTH, Issue 1 2001Ann-Sofi Matthiesen BSc Background:Newborns placed skin-to-skin with their mothers show an inborn sequence of behavior similar to that seen in other mammals. The purpose of this study was to make a detailed exploration of hand movements and sucking behavior in healthy term newborns who were placed skin-to-skin on their mothers' chests, and to study maternal oxytocin release in relation to these behaviors.Methods:Ten vaginally delivered infants whose mothers had not been exposed to maternal analgesia were video-recorded from birth until the first breastfeeding. Video protocols were developed based on observations of the videotapes. Each infant's hand, finger, mouth, and tongue movements, positions of the hand and body, and sucking behavior were assessed every 30 seconds. Maternal blood samples were collected every 15 minutes, and oxytocin levels were analyzed by radioimmunoassay. A statistical test for establishing the relationship between maternal oxytocin levels and infants' hand movements or sucking behavior was developed.Results:Infants used their hands to explore and stimulate their mother's breast in preparation for the first breastfeeding. A coordinated pattern of infant hand and sucking movements was also identified. When the infants were sucking, the massagelike hand movements stopped and started again when the infants made a sucking pause. Periods of increased massagelike hand movements or sucking of the mother's breast were followed by an increase in maternal oxytocin levels (p < 0.005). Conclusions:The findings indicate that the newborns use their hands as well as their mouths to stimulate maternal oxytocin release after birth, which may have significance for uterine contraction, milk ejection, and mother-infant interaction. [source] Effects of excessive glucocorticoid receptor stimulation during early gestation on psychomotor and social behavior in the rat ,DEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2010Karine Kleinhaus Abstract Severe psychological stress in the first trimester of pregnancy increases the risk of schizophrenia in the offspring. To begin to investigate the role of glucocorticoid receptors in this association, we determined the effects of the glucocorticoid dexamethasone (2,mg/kg), administered to pregnant rats on gestation days 6,8, on maternal behaviors and schizophrenia-relevant behaviors in the offspring. Dams receiving dexamethasone exhibited increased milk ejection bouts during nursing. Offspring of dexamethasone-treated dams (DEX) showed decreased juvenile social play and a blunted acoustic startle reflex in adolescence and adulthood, effects that were predicted by frequency of milk ejections in the dams. DEX offspring also showed increased prepulse inhibition of startle and reduced amphetamine-induced motor activity, effects not correlated with maternal behavior. It is postulated that over-stimulation of receptors targeted by glucocorticoids in the placenta or other maternal tissues during early gestation can lead to psychomotor and social behavioral deficits in the offspring. Moreover, some of these deficits may be mediated by alterations in postnatal maternal behavior and physiology produced by early gestational exposure to excess glucocorticoids. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52:121,132, 2010 [source] | ||||||||||