Infant, PrematureInfant, NewbornInfant, Premature, DiseasesInfant CareInfant FoodInfant FormulaInfant BehaviorInfant MortalitySudden Infant DeathInfant, Newborn, DiseasesInfant Nutritional Physiological PhenomenaInfant, Very Low Birth WeightInfant, Low Birth WeightBreast FeedingInfant WelfareDose-Response Relationship, DrugInfant, Extremely Low Birth WeightPregnancyMilk, HumanChild DevelopmentGestational AgeTime FactorsInfant, Extremely PrematureInfant, Small for Gestational AgeBottle FeedingDouble-Blind MethodBirth WeightIsofluraneAdministration, OralIntensive Care Units, NeonatalStructure-Activity RelationshipGuinea PigsCryingHalothaneStereoisomerismRats, Sprague-DawleyMothersRadiation DosageAlfentanilInfant Nutrition DisordersLethal Dose 50Respiratory Distress Syndrome, NewbornDrug InteractionsBronchopulmonary DysplasiaFentanylBinding, CompetitiveViper VenomsInjections, IntravenousInfectious Disease Transmission, VerticalUridine TriphosphateNeuromuscular Blocking AgentsDrug Administration ScheduleAtracuriumEnfluraneProspective StudiesRats, WistarDogsTreatment OutcomeMuscle ContractionIntensive Care, NeonatalAnalgesicsKineticsHeart RateSympathomimeticsDevelopmental DisabilitiesNitrous OxideMethyl EthersRadioligand AssayBlood PressureIncubators, InfantAnesthetics, InhalationNeuromuscular Nondepolarizing AgentsInfant EquipmentCells, CulturedReceptors, Neuropeptide YRabbitsRadiometryDiarrhea, InfantileNorepinephrinePropranololEnterocolitis, NecrotizingBrainEndothelinsAnalgesics, OpioidMother-Child RelationsMorphineRats, Inbred StrainsApneaFollow-Up StudiesSecretinMaternal BehaviorAnesthesia, InhalationRisk FactorsSucking BehaviorTerm BirthRetinopathy of PrematurityRetrospective StudiesPregnancy Complications, InfectiousPurinergic P2 Receptor AgonistsChromatography, High Pressure Liquid