Rapid Effects of Hypoxia on the Cerebrospinal Fluid Levels of Adenosine and Related Metabolites in Newborn and One-Month-Old Piglets

Laudignon, N; Farri, Evangelia; Beharry, Kay D.; Aranda, Jacob V.

doi:10.1159/000243322

Cited by 17 publications

(6 citation statements)

References 24 publications

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“…39±41 Caffeine may also block specific adenosine receptors increasing the susceptibility of the cell to hypoxia. 42 A recent literature review evaluating the association between caffeine consumption in pregnancy and IUGR emphasises that there is still a controversy as to whether caffeine is a risk factor for IUGR or not. 43 The author concluded that no study published to date is free of problems.…”

Section: Discussionmentioning

confidence: 99%

The influence of maternal nutritional factors on intrauterine growth retardation in Brazil

Rondó

Abbott

Rodrigues

et al. 1997

Paediatric Perinatal Epid

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A case-control study of 712 Brazilian mother-baby pairs was performed to assess maternal nutritional factors, more specifically low or marginal concentrations of vitamin A, folate and iron, as risk factors for intrauterine growth retardation (IUGR). Newborns were classified as being IUGR according to the Lubchenco classification. The gestational age of the newborns was evaluated by the Capurro method. Vitamin A, folate, ferritin and haemoglobin were measured by high-performance liquid chromatography, radioimmunoassay, immunoenzymetric assay and by the cyanmethaemoglobin method respectively. The relationship between maternal nutritional status and IUGR was investigated using stratification and logistic regression. According to the final logistic regression model, the risk factors for IUGR were: maternal body weight, per capita income, cigarette smoking, maternal weight gain, prior history of low birthweight, high maternal ferritin, beer intake and coffee intake. Specific interventions likely to have the major short-term impact in this region are not directly related to nutritional factors, but to efforts to reduce or eliminate toxic exposures. Over the long term, improvement in maternal nutritional status and socioeconomic conditions would be expected to produce important benefits.

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Section: Discussionmentioning

confidence: 99%

The influence of maternal nutritional factors on intrauterine growth retardation in Brazil

Rondó

Abbott

Rodrigues

et al. 1997

Paediatric Perinatal Epid

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“…Adenosine is a purine nucleoside that has long been established as a potent vasodilator in nearly all vascular beds studied, including the brain (Winn et al 1981a). In addition, plasma and intracerebral adenosine concentrations correlate inversely with arterial oxygen content in the fetal sheep (Kjellmer et al 1989;Koos et al 1994b;Suzuki & Power, 1999), newborn piglet (Laudignon et al 1991) and adult rat (Winn et al 1981b;Van Wylen et al 1986), providing evidence that adenosine is present in vasoactive concentrations during hypoxia. There are also numerous reports on the role of adenosine in regulation of cerebral blood flow during hypoxia in both the adult rat (Morii et al 1987;Simpson & Phillis, 1991;Coney & Marshall, 1998) and newborn piglet (Laudignon et al 1990;Park et al 1995;Bari et al 1998b).…”

mentioning

confidence: 94%

“…1989; Koos et al . 1994 b ; Suzuki & Power, 1999), newborn piglet (Laudignon et al . 1991) and adult rat(Winn et al .…”

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confidence: 99%

The Role of Adenosine in Regulation of Cerebral Blood Flow During Hypoxia in the Near‐Term Fetal Sheep

Blood

Hunter

Power

2002

The Journal of Physiology

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The aim of this study was to determine in the near-term ovine fetus the role of adenosine in the basal regulation of cerebral blood flow and in the increases in cerebral blood flow in response to acute hypoxic insult. We measured cerebral blood flow in chronically instrumented fetal sheep (127-135 days gestation, term ~145 days) using laser Doppler flowmetry probes implanted in the parietal cortices. Hypoxia was administered for 30 min by lowering the ewe's inspired oxygen to 10-12 % during an infusion of either saline or theophylline, a non-specific adenosine receptor antagonist. The theophylline infusion was begun 30 min prior to and ended 30 min after the completion of the hypoxic insult. The administration of theophylline had no significant effect on cerebral blood flow during the baseline period. During control hypoxic periods, cerebral blood flow increased by ~45 %. During theophylline experiments, however, there was no significant increase in cerebral blood flow during hypoxia. In the control experiments, cerebral blood flow returned to baseline levels during the recovery period, while in the theophylline experiments cerebral blood flow fell below baseline levels. We conclude that, in the near-term ovine fetus, adenosine plays a minimal role in the regulation of basal cerebral blood flow. However, these data are strong evidence for the involvement of adenosine in increased fetal cerebral blood flow during an acute hypoxic insult. Finally, adenosine may also play an important role in the maintenance of fetal cerebral blood flow immediately following hypoxic insult.

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“…Although our experiments do not support the hypothesis that the endogenous opioids mediate the regulated decrease in core temperature during acute hypoxemia in newborn and older guinea pigs, there are a number of other possibilities to consider. It is possible that other neuromodulators, such as histamine or adenosine, which are known to increase during hypoxemia (18,32,36) and which are known to influence thermoregulatory control (20,34), could mediate the regulated decrease in core temperature. Furthermore, as Tamaki and Nakayama (33) have shown that hypoxia increases the activity of warm-sensitive neurons in the preoptic area of the anterior hypothalamus, it is also possible that hypoxemia had a direct effect on these thermosensitive neurons and that this mediates the regulated decrease in core temperature.…”

Section: Discussionmentioning

confidence: 99%

“…Numerous mechanisms have been suggested for the regulated decrease in core temperature during acute hypoxemia, including a direct effect of hypoxemia on thermosensitive neurons in the preoptic area of the anterior hypothalamus (33) as well as the release of various neurotransmitters and/or neuromodulators in the central nervous system [e.g., arginine vasopressin (37), adenosine (18,34,36), histamine (20,32), and endogenous opioids (23)] that influence thermoregulation. Mayfield et al (23) have recently provided evidence that endogenous opioids participate in mediating the decrease in core temperature following acute severe hypoxemia in adult mice, produced by inhalation of 4.5% oxygen for 1.5, 2.0, and 2.5 min separated by 5 min of 21% oxygen.…”

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confidence: 99%

Naloxone does not alter the “regulated” decrease in core temperature during hypoxemia in guinea pigs

Crisanti

Fewell

1998

Journal of Applied Physiology

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In newborns and adults of a number of species, exposure to acute hypoxemia produces a "regulated" decrease in core temperature, the mechanism of which is unknown. The present experiments were carried out in chronically instrumented newborn (5-10 days of age; n = 59) and older (25-30 days of age; n = 61) guinea pigs to test the hypothesis that the endogenous opioids mediate this regulated decrease in core temperature. During an experiment, core temperature, oxygen consumption, and selected ambient temperature were measured in a thermocline (linear temperature gradient of 10-40 degreesC) during a control period of normoxemia, an experimental period of normoxemia or hypoxemia (inspired oxygen fraction 0.10), and during a recovery period of normoxemia following an intraperitoneal injection of naloxone hydrochloride (a nonspecific opioid antagonist; 1, 2, or 4 mg/kg) or vehicle. Naloxone did not significantly alter basal core temperature or the core temperature response to acute hypoxemia in newborn or older guinea pigs. Naloxone did, however, decrease basal oxygen consumption in newborn and older guinea pigs and altered the thermoregulatory effector mechanism used to decrease core temperature during hypoxemia in the newborn guinea pigs. Our data do not support the hypothesis that the endogenous opioids mediate the regulated decrease in core temperature that occurs in newborn and older guinea pigs during exposure to acute hypoxemia.

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Rapid Effects of Hypoxia on the Cerebrospinal Fluid Levels of Adenosine and Related Metabolites in Newborn and One-Month-Old Piglets

Cited by 17 publications

References 24 publications

The influence of maternal nutritional factors on intrauterine growth retardation in Brazil

The influence of maternal nutritional factors on intrauterine growth retardation in Brazil

The Role of Adenosine in Regulation of Cerebral Blood Flow During Hypoxia in the Near‐Term Fetal Sheep

Naloxone does not alter the “regulated” decrease in core temperature during hypoxemia in guinea pigs

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