Nonmigrating Rhythmic Activity in the Stomach and Duodenum of Neonates

Tomomasa, Takeshi; Koizumi, Toru; Kuroume, Takayoshi

doi:10.1159/000242145

Cited by 77 publications

(37 citation statements)

References 5 publications

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“…These data were compatible with studies in humans, showing that the intraluminal pressures achieved in the stomach are greater in adults compared to neonates (2). The age-related changes in gastric smooth muscle physiology that are responsible for increasing contraction have not been examined.…”

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confidence: 82%

Development of Calcium Channels in Gastric Smooth Muscle

et al. 1989

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ABSTRACT. We used [3H]nitrendipine to characterize dihydropyridine sensitive calcium channels on cells isolated from neonatal (1 d) and weanling (11 wk) rabbit gastric fundic and antral smooth muscle. Incubating with and without nifedipine 20 pM, specific binding was 56 + 4% of total binding at 0.1 nM [3H]nitrendipine. Specific binding was saturable, reversible, achieved equilibrium by 10 min at 4"C, and was linearly related to cell concentration. The affinity constant for [3H]nitrendipine was higher in weanling fundus (kd = 243 f 121 pM) versus antrum (kd = 771 + 190 pM), p < 0.05. There were no age-related changes in affinity. In the antrum, the number of binding sites (B,,,) increased from 6 000 + 266/cell in neonates to 27 500 f 8 440/cell in weanlings (p < 0.05). In the fundus B, , , was 7 750 + 2 100/cell in neonates, and there was no age-related change. To assess function, we compared isometric stress in full thickness muscle strips oriented to the circular layer. Bethanechol stimulated dose-dependent tonic contractions in the fundus and phasic contractions in the antrum. Maximal stress increased with age from 305 + 54 mN/cm2 to 1140 + 73 mN/cmZ (p < 0.05) in the fundus and from 72 f 20 mN/cm2 to 154 f 30 mN/cm2 (p < 0.05) in the antrum. Preincubation and incubation without calcium resulted in reversible inhibition of contraction at both ages. Nifedipine 10-pM inhibited 100% of bethanechol-stimulated contraction in the antrum, but only 25% in the fundus at both ages. In summary, in rabbit gastric smooth muscle: 1 ) 13H]nitrendipine identified functional calcium channels in neonates and weanlings, 2) there are age-related increases in calcium channels on antral, but not on fundic cells, 3) there are age-related increases in stress in strips from antrum and fundus, 4) the fundus utilizes intracellular calcium stores for bethanechol-stimulated contraction, whereas the antrum requires extracellular calcium. Age-related increases in dihydropyridine sensitive calcium channels are consistent with the requirement of the antrum for extracellular calcium to support contraction. (Pediatr Res 25:600-604, 1989) In muscle strips from rabbit stomach, maximal contraction was greater in adult compared to newborn animals (1). These data were compatible with studies in humans, showing that the intraluminal pressures achieved in the stomach are greater in adults compared to neonates (2). The age-related changes in gastric smooth muscle physiology that are responsible for increasing contraction have not been examined.

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confidence: 82%

Development of Calcium Channels in Gastric Smooth Muscle

et al. 1989

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“…Although premature neonates have been noted to be more likely than term neonates to suffer from feed intolerance, regurgitation and gastro‐oesophageal reflux, the causes of this may be altered feedback from the proximal small intestine and intolerance to the high fat content of preterm infant formulas rather than any impairment of gastric motility 25, 26, 27. Lange et al .…”

Section: Introductionmentioning

confidence: 99%

Does age affect gastric emptying time? A model‐based meta‐analysis of data from premature neonates through to adults

Bonner

Vajjah

Abduljalil

et al. 2015

Biopharm & Drug Disp

124

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Purpose. Gastric emptying (GE) is often reported to be slower and more irregular in premature neonates than in older children and adults. The aim of this study was to investigate the impact of age and other covariates on the rate of GE. Methods. The effect of age on the mean gastric residence times (MGRT) of liquid and solid food was assessed by analysing 49 published studies of 1457 individuals, aged from 28 weeks gestation to adults. The data were modelled using the nonlinear mixed‐effects approach within NONMEM version 7.2 (ICON, Dublin, Ireland), with evaluation of postnatal age, gestational age and meal type as covariates. A double Weibull function was selected as a suitable model since it could account for the typical biphasic nature of GE. Results. Age was not a significant covariate for GE but meal type was. Aqueous solutions were associated with the fastest emptying time (mean simulated gastric residence time of 45 min) and solid food was associated with the slowest (98 min). Conclusions. These findings challenge the assertion that GE is different in neonates, as compared with older children and adults due to age, and they reinforce the significance of food type in modulating GE. © 2015 The Authors. Biopharmaceutics & Drug Disposition Published by John Wiley & Sons Ltd.

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“…The relatively low feeding volume during the first hours of life, coinciding with the physiologic diuresis of excess extracellular fluid that accompanies the transition from prenatal to postnatal life, may be caused by one or more factors, including a lack of hunger or thirst because of CNS depression or arousal, changing hormone concentrations associated with parturition, or immaturity of gastric function. Despite the appearance of anatomic features of the digestive tract early in fetal life (1, 2), many aspects of gastrointestinal motility are immature in the neonate (3)(4)(5)(6). In vitro studies demonstrated rapid postnatal changes in the receptors (7,8) and responses to agonists in rabbit gastric muscle (9,10).…”

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confidence: 99%

Rapid Maturation of Gastric Relaxation in Newborn Infants

et al. 2001

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We studied gastric volume, wall compliance, sensory perception, and receptive relaxation during the first postnatal 80 h in 17 healthy term infants, using a computer-driven air pump and simultaneously measuring pressure and volume within a latex balloon placed through the oropharynx into the stomach. To evaluate gastric compliance, we measured pressures while we infused air into the intragastric balloon at different rates (10, 20, and 60 mL/min) in random sequence. In all infants, there was a linear relationship between intragastric pressure and volume to the maximum pressure tested, 30 mm Hg. Gastric compliance ranged from 0.2 mL/mm Hg to 3.8 mL/mm Hg. Different infusion rates had no effect on compliance. We calculated gastric receptive relaxation by measuring the volume needed to maintain a constant pressure of 10 mm Hg within the balloon for 5 min. Gastric receptive relaxation ranged from 0.5 mL/min to 54 mL/min. Gastric compliance and receptive relaxation increased with postnatal age (r ϭ 0.70, p Ͻ 0.005; r ϭ 0.79, p Ͻ 0.001, respectively) and with number of feedings (r ϭ 0.80, r ϭ 0.88, respectively, both p Ͻ 0.001). There was no correlation between weight or type of feeding (breast versus formula) and either gastric compliance or relaxation. In conclusion, these results may explain the small feedings that neonates ingest in the first days of life. During the first 3 postnatal d, the newborn stomach becomes more compliant and develops more receptive relaxation, associated with a larger volume capacity. In healthy neonates, the volume of feedings in the first days of life is 60 -100 mL/kg per day or about 20 -40 mL per feeding. After a few days, the healthy neonate ingests approximately 150 mL/kg per day, or about 75 mL per feeding. The relatively low feeding volume during the first hours of life, coinciding with the physiologic diuresis of excess extracellular fluid that accompanies the transition from prenatal to postnatal life, may be caused by one or more factors, including a lack of hunger or thirst because of CNS depression or arousal, changing hormone concentrations associated with parturition, or immaturity of gastric function. Despite the appearance of anatomic features of the digestive tract early in fetal life (1, 2), many aspects of gastrointestinal motility are immature in the neonate (3-6). In vitro studies demonstrated rapid postnatal changes in the receptors (7,8) and responses to agonists in rabbit gastric muscle (9, 10). One potential explanation for the small voluntary feeding volumes in the hours immediately after birth is an immaturity of gastric relaxation to accommodate the entry of a meal.In healthy children and adults, the gastric fundus and body relax as a meal enters, so that there is little increase in intragastric pressures over a wide range of volumes (11-13). Azpiroz and Malagelada (12, 13) used a computer-driven air pump to infuse air into a noncompliant balloon placed in the stomach . Pressures increased initially as the stomach started to fill. As the stomach continued to fi...

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Nonmigrating Rhythmic Activity in the Stomach and Duodenum of Neonates

Cited by 77 publications

References 5 publications

Development of Calcium Channels in Gastric Smooth Muscle

Development of Calcium Channels in Gastric Smooth Muscle

Does age affect gastric emptying time? A model‐based meta‐analysis of data from premature neonates through to adults

Rapid Maturation of Gastric Relaxation in Newborn Infants

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