Fetal experience with milk or an artificial nipple alters appetitive and aversive responses to perioral cutaneous stimuli

Fetal rats exhibit oral grasping of an artificial nipple. The authors examined interactive effects of sensory stimuli normally encountered in the suckling environment on subsequent responses to the nipple. Embryonic Day 20 rat fetuses received an infusion of milk, lemon, or saline through a hollow artificial nipple or an intraoral cannula (producing no nipple stimulation). One minute after sensory pretreatment, behavioral responses of fetuses to an artificial nipple were recorded on videotape for frame-by-frame analysis. Preexposure to the artificial nipple decreased the number of oral grasps and facial wipes directed toward the artificial nipple but increased the duration of grasp responses. Milk uniformly reduced fetal responsiveness to the nipple. Furthermore, the artificial nipple enhanced fetal responses to perioral cutaneous stimulation, whereas milk suppressed perioral responsiveness. These data suggest that the perinatal rat's 1st experience with milk or the nipple can alter subsequent responses to suckling stimuli.     

Kappa opioid mediation of fetal responses to milk.

A series of experiments provided evidence for the existence of a functional opioid system in the fetal rat near term. Application of a tactile probe to the perioral region of the fetus consistently evoked a stereotypic facial wiping response. Administration of low dosages of morphine to the fetus had little effect on nonevoked motor activity but reduced fetal responsiveness to cutaneous stimulation. Milk infused into the mouth of the fetus reduced fetal responsiveness to the tactile probe. Milk's effect on cutaneous responsiveness was reversed by injection of the nonspecific opioid antagonist naloxone. The effect of milk on fetal responsiveness to cutaneous stimulation was reversed by the kappa opioid antagonist nor-binaltorphimine, but not by the mu antagonist β-funaltrexamine. Milk engages the endogenous opioid system of the fetal rat and affects fetal responsiveness by interacting with the kappa receptors of the opioid system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endogenous AVP systems regulate oral behavior in the rat fetus: Neuropeptide systems as ontogenetic adaptations.

Pharmacological manipulation of V? receptors in rostral and caudal brain regions alters perioral responsiveness in the E20 rat fetus. Blockade of caudal V? receptors or activation of rostral V? receptors reduces fetal responsiveness to perioral cutaneous stimulation. Activation of caudal V? receptors or blockade of rostral V? receptors increases fetal responsiveness to perioral stimulation, including oral capture and grasping of an artificial nipple. These results suggest that V? receptor-containing neurons regulate perioral responsiveness in the E20 rat fetus and that the 2 populations of neurons exhibit functional differences. The caudal part of the arginine–8-vasopressin (AVP) system increases whereas the rostral part decreases responsiveness to different types of perioral stimuli. The neuropeptide AVP may affect suckling behavior immediately after birth by regulating perioral sensory responsiveness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioned opioid activity in the rat fetus.

Classical conditioning in the rat fetus (Embryonic Day 20) was investigated in 4 experiments. Reexposure to a CS (sucrose), after 3 pairings with an unconditioned stimulus (UCS; milk), reduced fetal facial wiping in a bioassay of perioral cutaneous responsiveness. Reduced responsiveness was evident only in Ss that received paired presentations of the CS and UCS and cannot be attributed to habituation, sensitization to the CS, or protracted effects of UCS exposure during conditioning trials. Fetuses attended to the chemosensory, not the tactile, qualities of the sucrose infusion during CS reexposure. Changes in fetal responsiveness resulted from conditioned activity in the endogenous opioid system, specifically at mu opioid receptors. These data confirm that the rat fetus is capable of exhibiting a conditioned opioid response in utero. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Classical conditioning of opioid activity in the fetal rat.

Milk promotes activity in the kappa opioid system of the rat fetus that reduces responsiveness to cutaneous stimulation. In this study, fetuses on Gestational Day 20 were presented with an artificial nipple (conditioned stimulus [CS]) paired with an intraoral infusion of milk (unconditioned stimulus [UCS]). One paired presentation of the CS and UCS reduced fetal responsiveness after reexposure to the CS. Selective antagonism of opioid receptors after conditioning indicated that reduced responsiveness was due to mu opioid activity. Mu and kappa opioid activity was evident after 3 paired presentations of CS and UCS and reexposure to milk. Kappa opioid activity during conditioning was necessary for mu involvement after reexposure to the CS or UCS. These experiments, which were conducted with fetal Ss that lacked suckling experience, suggest that neurochemical systems engaged during suckling may change rapidly after the newborn's initial experiences at the nipple. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Classical conditioning in the fetal rat: Reinforcing properties of dynorphin A (1–13).

This study examined the reinforcing properties of dynorphin A (1-13) in a single-trial classical conditioning paradigm in the E20 rat fetus. Injection of dynorphin into the cisterna magna increased fetal motor activity and reduced facial wiping in a test of perioral cutaneous responsiveness. Dynorphin was effective as an unconditioned stimulus (US) in a classical conditioning paradigm using an artificial nipple conditioned stimulus (CS) and dynorphin A (1-13) US. The association between CS and US was dependent on activity in the kappa opioid system. Re-exposure to the artificial nipple CS after a single pairing of the nipple with dynorphin resulted in conditioned activation of the kappa opioid system. Dynorphin A (1-13) functions as a reinforcer for classical conditioning in the rat fetus after intracisternal or intrahemispheric injection with the conditioned response depending on route of administration and site of injection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prenatal expression of species-typical action patterns in the rat fetus (Rattus norvegicus).

We investigated sensory and behavioral responsiveness of the rat fetus. On Days 19, 20, or 21 of gestation, rat fetuses received intraoral infusions of a biologically important stimulus, milk, or a novel chemical stimulus, lemon. Using a technique to directly observe behavior in utero, we found that rat fetuses discriminate between intraoral infusions of milk and lemon, exhibiting different levels and patterns of overall activity after infusion. Milk was found to evoke a low magnitude, delayed increase in overall fetal activity from Day 19 through Day 21, whereas lemon evoked a high-magnitude, spiked pattern of activity that diminished from Day 19 to Day 21. Late in gestation these two stimuli elicited species-typical action patterns. Milk infusions elicited a stretch response much like the one shown by pups at the nipple; lemon infusions elicited face wiping typical of older pups and adults exposed to aversive gustatory stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioural context and a distributed system: Metabolic mapping studies of the basal ganglia.

Used metabolic mapping to determine if a distributed, anisotropic pattern of striatal processing would be affected by behavioral context. Male rats were trained, in a particular environment, to make licking movements in a situation where accurate performance depended upon sensory feedback from the perioral/vibrissa area. Probe stimulation of the perioral/vibrissa area was presented noncontingently to these Ss when they were at rest in the training environment. The resulting pattern of striatal activation was compared with that of untrained Ss receiving physically equivalent probe stimuli. The study found that behavioral context affected the way in which the striatum processes somatosensory information, within a relatively large somatosensory territory of the striatum. An overall map of the striatum that localizes changes related to this remarkable phenomenon of contextual responses contributes to the understanding of anatomical substrates of neural systems that integrate information, and may lead to new striatal regions to study synaptic mechanisms of learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Habituation to chemosensory stimuli in the rat fetus: Effects of endogenous kappa opioid activity.

On Day 21 of gestation, rat fetuses respond to chemosensory stimuli by expressing stereotypic facial wiping behavior. A series of 4 experiments was conducted to investigate (1) the influence of morphine on fetal responsiveness to a single chemosensory infusion, (2) the effect of naloxone blockade of endogenous opioid activity on diminished fetal responsiveness over a series of chemosensory infusions, (3) the effect of endogenous opioids on the recovery of fetal responsiveness to infusion after various dishabituation procedures, and (4) the influence of selective mu and kappa opioid receptor antagonists on fetal habituation. These experiments confirm that fetuses habituate after a brief series of chemosensory infusions and that dishabituation promoted by presentation of a novel stimulus is facilitated by pharmacological blockade of kappa opioid receptors. Endogenous activity in the kappa opioid system may be functional in modulating the sensory environment around the time of birth. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decreased amniotic fluid volume at < 32 weeks of gestation is associated with decreased fetal movements

The objective of this study was to assess the relationship between amniotic fluid volume (AFV) and fetal movements at < 32 weeks gestation as assessed by routine biophysical profile (BPP). From a database of 465 consecutive nonhypertensive, nondiabetic patients delivering at < 32 weeks gestation, patients with singleton, nonanomalous fetuses with AFV and fetal movements determined as part of a BPP assessment within 24 hours of delivery were studied. Amniotic fluid volume was scored 0 to 2, according to the following criteria: largest pocket in vertical diameter < 1 cm = 0; < 2 but > 1 cm = 1; > or = 2 cm = 2. Fetal movements (FM) were scored over 30 minutes: 0 if absent, 1 if 1 to 2 movements, 2 if > or = 3 gross (limb/trunk) movements. Variables assessed included fetal presentation, gestational age (GA), premature rupture of membranes (PROM) as a principal indication for delivery, clinical chorioamnionitis (diagnosed by previously published criteria), histologic parameters of infection (in amnion and umbilical cord assessed by a single pathologist blinded to clinical data), and neonatal outcome. Statistical analyses included contingency tables and analysis of variance with p < 0.05 considered significant. Three hundred and fifty-two patients met the inclusion criteria. One hundred and sixty-seven patients (47%) had PROM as a primary indication for delivery. Infrequently, decreased fetal well-being manifested by a BPP < 7 of 10 points was an indication for delivery despite prematurity (n = 7). Of the 352 patients, 80 (23%) had AFV = 0, 60 (17%) had AFV = 1, and 212 (60%) had AFV = 2; and 12 (3%) had FM = 0, 30 (9%) FM = 1, and 310 (88%) FM = 2. There was a significant correlation between decreased AFV and decreased fetal movements (p < 0.0001). Fetal presentation and GA were not significantly different between patients based on score of fetal movements. The incidence of clinical chorioamnionitis was significantly greater in patients with FM = 0 (p < 0.005). We conclude that decreased AFV is associated with decreased fetal movements irrespective of fetal presentation or gestational age. Neonatal outcome (umbilical vasculitis, sepsis, intraventricular hemorrhage) is affected only in unusual cases in which otherwise uncompromised (nonhypoxic, nonacidotic) fetuses have low scores on both these antepartum ultrasonographic parameters.     

Combined one- and two-dimensional ultrasound system for monitoring fetal breathing movements

A combined one- and two-dimensional ultrasonic system for monitoring respiratory movements in the human fetus has been developed. A real-time cross-sectional image of the fetal chest at the level of the fetal heart can be obtained, and a time motion recording of fetal respiratory movements can then be written on a strip-chart recorder. Combining the features of one-dimensional and two-dimensional systems produces an accurate means of investigating fetal breathing movements.     

5-Hydroxytryptamine1D-like receptors mediate contraction of partially depolarized rabbit renal arteries

OBJECTIVE: Our purpose was to correlate measures of Doppler-detected fetal movements with standard fetal heart rate parameters and perinatal outcomes. STUDY DESIGN: This prospective, multiinstitutional trial used the Hewlett-Packard M1350A monitor to record simultaneous fetal heart rate baseline, variability, accelerations, decelerations, and number of fetal movements, and duration and percent of total time. These data were compared at 10- and 30-minute intervals during nonstress tests and were correlated with fetal heart rate baseline parameters and maternally perceived fetal movements and with outcomes of infants delivered within 7 days of the last test. RESULTS: At six centers 1704 actocardiograms from 884 third-trimester patients were analyzed. Doppler-detected fetal movement counts, durations, and percent of total time correlated weakly with all baseline fetal heart rate parameters (all values < 0.20). All fetal movement parameters increased significantly in successive 10-minute blocks and in periods of increased or normal fetal heart rate variability compared with those with fetal heart rate variability. The sensitivity, specificity, and predictive values of the percent of total movement time were comparable to those of standard nonstress test parameters. The risk of poor perinatal outcomes after nonreactive nonstress tests was lower in cases with fetal movements than in those without. CONCLUSIONS: Doppler actocardiography may help to discriminate fetal states during antepartum testing. It may prevent inappropriate diagnosis of fetal compromise when the nonstress test is nonreactive or nonreassuring.     

The components of the phenotypic dispersion of the basic typological traits and of work capacity in horses of the Ukrainian saddle breed

INTRODUCTION: The four-channel-tocography was developed to register the spatial and temporal pattern of uterine contractions and to evaluate their clinical relevance. In this study it should be assessed whether the four-channel-tocography can also register fetal movements. MATERIAL AND METHODS: The study included 38 women with a gestational age between 28 and 43 weeks and singleton pregnancy. Four pressure transducers were attached in a square around the umbilicus. Parallel to the continuous registration of four-channel-tocography fetal movements were observed by conventional ultrasound. RESULTS: In a total of 23 hours and 11 minutes 403 fetal movements were registered by ultrasound and 405 by four-channel-tocography. 17% of the ultrasonically observed fetal movements were documented by the four-channel-tocography and 70% of the tocographically registered movements could be verified by ultrasound. CONCLUSION: Fetal movements can be registered by four-channel-tocography with good sensitivity and reliability. Essential for its clinical use is an automatic analysis, which is being developed.     

Kinetocardiotocography--follow-up of diazepam poisoning

Report about continuous fetal monitoring of heart rate and movements 9-30 hours after diazepam-intoxication. in an early stage after intoxication fetal movements are associated with FHF-decelerations, later on with accelerations. A sinusoidal like pattern may be caused by fetal suckling movements.     

Opioid control of the fetal stretch response: Implications for the first suckling episode.

On their 1st experience with milk, fetal rats express a stretch response that is similar to the postnatal behavior exhibited by infant rats at the nipple. Fetuses also possess a functional opioid system that is activated by prenatal milk exposure. The opioid receptor antagonist naloxone and the specific kappa antagonist nor-binaltorphimine blocked the stretch response and prevented the increase in rearlimb activity that is typically induced by milk. The mu antagonist β-funaltrexamine blocked the stretch while permitting the expression of rearlimb activity. The kappa agonist U50,488 promoted rearlimb activity in the absence of milk, whereas the mu agonist [{d}-Ala–2,NMe-Phe–4,Gly–5-ol]-enkephalin (DAMGO) exerted little influence on fetal behavior. Fetuses pretreated with U50,488 stretched to nonmilk stimuli (saline or lemon), but fetuses pretreated with DAMGO did not. Opioid activation is part of a chain of events that culminates in the fetal stretch response and may be important in promoting milk ingestion during the newborn's 1st suckling episode. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experience-induced fetal plasticity: The effect of gestational ethanol exposure on the behavioral and neurophysiologic olfactory response to ethanol odor in early postnatal and adult rats.

Human fetal ethanol exposure is strongly associated with ethanol avidity during adolescence. Evidence that intrauterine olfactory experience influences chemosensory-guided postnatal behaviors suggests that an altered response to ethanol odor resulting from fetal exposure may contribute to later abuse risk. Using behavioral and neurophysiological methods, the authors tested whether ethanol exposure via the dam's diet resulted in an altered responsiveness to ethanol odor in infant and adult rats. Compared with controls, (a) fetal exposure tuned the neurophysiologic response of the olfactory epithelium to ethanol odor at some expense to its responsiveness to other odorants in infantile rats--this effect was absent in adults; (b) the neural effect in infantile rats was paralleled by an altered behavioral response to ethanol odor that was specific to this odorant--this effect was also absent in adults; and (c) a significant component of the infantile behavioral effect was attributable to ethanol's effect on the olfactory neural modality. These data provide evidence for an important relationship between prenatal ethanol experience and postnatal behavioral responsiveness to the drug that is modulated or determined by olfactory function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fetomaternal macrotransfusion--a cause for decreased fetal movements. 2 cases

Two cases of fetomaternal macrotransfusion in otherwise normal pregnancies are reported. In both cases the main symptoms observed by the patients were decreasing fetal movements. Cardiotocography revealed a highly pathologic pattern an immediate cesarean section was performed. The cause of massive fetomaternal hemorrhage (390 and 635 ml fetal blood) remains unclear. Delayed treatment leads to severe anemia followed by hypovolemic shock and ultimately to stillbirth. Pregnancies complicated by fetomaternal hemorrhage develop normally until signs of fetal decompensation begin to appear. Decreasing fetal movements in the most common symptom reported by the patients. In addition to a contraction-stress-test, blood from the pregnant women should be looked at for fetal erythrocytes, a test that can be performed very quickly and easily. If the fetus is viable, immediate delivery should be performed and blood transfusions to the newborn should be administered. In preterm pregnancies cordocentesis and intrauterine blood transfusion may be considered.     

Causality and control: key to the experiment

Maternal betamethasone administration causes a transient but considerable reduction in fetal body and breathing movements and in fetal heart rate variation. The aim of the present prospective study was to investigate whether there is evidence of circulatory changes in fetal, placental or uterine arteries, consistent with hypoxemia. Eighteen women at risk for preterm delivery received betamethasone to enhance fetal lung maturation. Doppler studies were performed before treatment, and 24 and 72 h after the second dose of betamethasone. Blood flow velocity waveforms were obtained from both uterine arteries, umbilical arteries, fetal descending aorta, fetal renal artery, and fetal cerebral arteries. No significant changes occurred in the pulsatility index of any of these blood vessels, suggesting that the transient reduction in fetal heart rate variation and fetal body and breathing movements following maternal betamethasone administration is not mediated through fetal hypoxemia.     

Trigeminal orosensation and ingestive behavior in the rat.

Used a deafferentation procedure with male Wistar rats to examine the contributions of trigeminal orosensation to control of ingestive behavior. The procedure removed somatosensory input from the mouth while sparing olfaction, lingual taste, vibrissae inputs, and proprioceptive afferents from and efferents to the jaw muscles. Ss with sections of tongue or jaw muscle efferents served as controls. Bilateral trigeminal orosensory deafferentation was followed by effects on ingestive behavior, the magnitudes of which were proportional to the extent of the deafferentation. The trigeminal syndrome includes aphagia and adipsia, impairments in the sensorimotor control of eating and drinking, decreased responsiveness to food and water, and a reduction in the level of body weight regulation. Trigeminal deafferentation spared elementary ingestive movement patterns (biting, licking, and chewing) but disrupted their control by the perioral stimuli. Deficits in food intake varied with the sensory properties of the diet. Recovery of intake took place along a palatability gradient, and recovery of water intake paralleled that of dry food. The chronically reduced body weight was caused by persistent hypophagia and reflected reduced responsiveness to food. Findings suggest a considerable degree of overlap in the neural mechanisms mediating the sensorimotor and motivational control of intake in the rat. (76 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acute maternal alcohol consumption disrupts behavioral state organization in the near-term fetus

Disturbed sleep regulation is often observed in neonates of women who drank heavily during pregnancy. It is unknown if (and how) an occasional drink affects fetal sleeping behavior. In 28 near-term pregnant women we examined the effects on fetal behavioral state organization of two glasses of wine (0.25 g of ethanol/kg of maternal body weight). Simultaneous 2-h recordings of fetal heart rate and body, eye, and breathing movements were made on two successive days, once without alcohol exposure and once during maternal alcohol consumption. The study was standardized for time of day and fetal sleep state, i.e., the start of recording was either during quiet sleep (n = 16) or during active sleep (n = 12). Alcohol intake reduced fetal eye movements, disorganized behavioral state organization (rapid eye movement sleep was affected in particular), and suppressed fetal breathing activity almost completely. Modest maternal alcohol intake affects fetal behavioral state organization, which reflects an immediate effect on fetal brain function.