Effect of Morphine on Fetal Electrocortical Activity and Breathing Movements in Fetal Sheep

Toubas, Paul L.; Pryor, Ami L.; Sheldon, Roger E.

doi:10.1159/000457029

Cited by 8 publications

(3 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An alterna tive hypothesis is that mu receptors may be relatively deficient in the fetus and periph eral delta receptors may be concentrated along parasympathetic nerves and ganglia as compared to sympathetic efferents. Postnatally, mu receptor numbers may increase while delta receptors are redistributed more densly along sympathetic nerve terminals, ganglia and the adrenal medulla where they may mediate catecholamine release [17], This concept is compatible with the late overall maturation of the sympathoadrenal system during the final quarter of gestation and early postnatal period [22][23][24][25], The incidence of baseline FBM which we have recorded is less than that previously reported [27], This difference appears to be related to the manner in which the incidence was calculated. During the basal state, iso lated infrequent FBM of short duration may be observed.…”

Section: Discussionsupporting

confidence: 65%

“…[26] have noted similar increases in respiratory rates follow ing meth-enkephalin administration in con scious dogs. Recent studies in fetal sheep also have reported the onset of regular, con tinuous FBM associated with increases in low-voltage, high-frequency electrocortical activity following either morphine or metha done administration [27,28]. Somewhat dif ferent results were reported by DeBoeck et al [29], who observed partial reversal of hypoxemia-induced respiratory depression in healthy, full-term human neonates by nal oxone.…”

Section: Discussionmentioning

confidence: 95%

See 1 more Smart Citation

Fetal Cardiovascular and Breathing Movement Responses to Endogenous Opiates

Lewis¹,

Ferry²,

Sadeghi³

1986

Neonatology

View full text Add to dashboard Cite

Endogenous opiates have been shown to alter cardiopulmonary activity in a variety of animal models. The present investigation in fetal sheep evaluated the response of heart rate, blood pressure and breathing movements (FBM) to central nervous and intravenous meth-enkephalin and β-endorphin. Marked bradycardia was noted within 3–5 s of intravenous meth-enkephalin administration and lasted less than 10–15 s. An 84.8 ± 19.0% prolongation in cardiac cycle length was observed after 20 nmol/kg meth-enkephalin (p < 0.02). In contrast, there was no significant change in heart rate following 2–50 nmol/kg β-endorphin. The meth-enkephalin-induced slowing of heart rate was virtually eliminated by autonomic blockade with atropine or hexamethonium but merely partially blunted by naloxone. FBM were not altered by intravenous administration of either opiate. However, both meth-enkephalin and β-endorphin produced a dramatic increase in FBM following injection into the cisterna magna. Prior to opioid administration, FBM were noted 11 ± 1.4% of the time. Intracisternal opiates resulted in a 43.9 ± 10.1% incidence of FBM for up to 60 min. Parasympathetic blockade with atropine had no effect on the pattern of FBM following intracisternal opiate administration whereas naloxone terminated the increased respiratory activity within 1 min. These data suggest a potential role for endogenous opiates in the modulation of fetal cardiorespiratory function.

show abstract

Section: Discussionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 95%

Fetal Cardiovascular and Breathing Movement Responses to Endogenous Opiates

Lewis¹,

Ferry²,

Sadeghi³

1986

Neonatology

View full text Add to dashboard Cite

show abstract

“…The fetal lamb is frequently used to study the effects of chronic opiate exposure on respiratory and sleep-wake cycles (Hasan et al 1990;Olsen et al 1988;Szeto et al 1988;Toubas et al 1985;Umans and Szeto 1983). In opiate-infused fetal lambs, a characteristic opiate withdrawal syndrome was observed, which included increased movement and neck tone, eye movements, tachypnea, bradycardia, hypertension, and passage of meconium (stool) into the amniotic fluid followed by naloxone-precipitated withdrawal (Umans and Szeto 1985).…”

Section: Lambmentioning

confidence: 99%

Neonatal Animal Models of Opiate Withdrawal

Richardson¹,

Yohay²,

Gauda³

et al. 2006

ILAR Journal

View full text Add to dashboard Cite

The symptoms of opiate withdrawal in infants are defined as neonatal abstinence syndrome (NAS). NAS is a significant cause of morbidity in term and preterm infants. Factors, such as polysubstance abuse, inadequate prenatal care, nutritional deprivation, and the biology of the developing central nervous system contribute to the challenge of evaluating and treating opiate-induced alterations in the newborn. Although research on the effects of opiates in neonatal animal models is limited, the data from adult animal models have greatly contributed to understanding and treating opiate tolerance, addiction, and withdrawal in adult humans. Yet the limited neonatal data that are available indicate that the mechanisms involved in these processes in the newborn differ from those in adult animals, and that neonatal models of opiate withdrawal are needed to understand and develop effective treatment regimens for NAS. In this review, the behavioral and neurochemical evidence from the literature is presented and suggests that mechanisms responsible for opiate tolerance, dependence, and withdrawal differ between adult and neonatal models. Also reviewed are studies that have used neonatal rodent models, the authors' preliminary data based on the use of neonatal rat and mouse models of opiate withdrawal, and other neonatal models that have been proposed for the study of neonatal opiate withdrawal.

show abstract

Current Concepts in Substance Abuse During Pregnancy

Szeto¹

1990

Current Perinatology

View full text Add to dashboard Cite

Effect of Morphine on Fetal Electrocortical Activity and Breathing Movements in Fetal Sheep

Cited by 8 publications

References 14 publications

Fetal Cardiovascular and Breathing Movement Responses to Endogenous Opiates

Fetal Cardiovascular and Breathing Movement Responses to Endogenous Opiates

Neonatal Animal Models of Opiate Withdrawal

Current Concepts in Substance Abuse During Pregnancy

Contact Info

Product

Resources

About