Carotid chemoreceptor response to natural stimuli in the newborn kitten

Marchal, François; Bairam, Aïda; Haouzi, Philippe; Crance, J. P.; Giulio, Camillo Di; Vert, P; Lahiri, S.

doi:10.1016/0034-5687(92)90058-5

Cited by 68 publications

(46 citation statements)

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“…Similarly, a shift of the POµ response curve upwards and to the right was observed in older kittens. More recently, postnatal maturation of steady-state COµ sensitivity has been reported (Marchal et al 1992;Carroll et al 1993;Pepper, Landauer & Kumar, 1995). Marchal et al (1992) recorded from single chemoreceptor fibres in anaesthetized newborn kittens at two different ages and at three levels of inspired COµ in oxygen.…”

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confidence: 98%

“…More recently, postnatal maturation of steady-state COµ sensitivity has been reported (Marchal et al 1992;Carroll et al 1993;Pepper, Landauer & Kumar, 1995). Marchal et al (1992) recorded from single chemoreceptor fibres in anaesthetized newborn kittens at two different ages and at three levels of inspired COµ in oxygen. Chemoreceptor discharge increased when the partial pressure of COµ (PCOµ) increased, and the response of kittens aged 10 days or older was greater than the response for kittens under 10 days old.…”

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confidence: 98%

“…This is explicable in terms of the bicarbonate hypothesis (Torrance et al 1993), which predicts a brisk response to COµ with a relatively greater adaptation to a steady-state level in high oxygen and less in hypoxia. The neonatal response to hypoxia and the postnatal resetting of hypoxia chemosensitivity has been extensively documented (Blanco, Dawes, Hanson & McCooke, 1984;Kumar & Hanson, 1989;Marchal, Bairam, Haouzi, Crance, Di Giulio, Vert & Lahiri, 1992;Carroll, Bamford & Fitzgerald, 1993). Blanco et al (1984) showed that spontaneous chemoreceptor discharge was present at a Pa,Oµ of ca 25 mmHg in fetal lambs from as early as 90 days gestation, but the chemoreceptor partial pressure of Oµ (POµ) response curve was displaced to the left of that measured in the adult.…”

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confidence: 99%

“…Resetting of carotid body sensitivity to hypoxia occurred over the next few days. Marchal et al (1992) measured single fibre chemoreceptor activity in kittens less than and greater than 10 days old at three Pa,Oµ levels (330, 100 and 50 mmHg), and found that it was less in the younger kittens at Pa,Oµ 100 and 50 mmHg, but not at 330 mmHg. The POµ response curve was displaced upwards and to the right in older kittens.…”

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confidence: 99%

“…In contrast, the dynamic response of the carotid body to COµ has been less thoroughly investigated in the neonate. Marchal et al (1992) measured the time taken to reach a steady-state level of chemoreceptor discharge after the application of 5 or 10% COµ in oxygen. They found no adaptation, and inferred that the newborn kitten does not possess a dynamic chemosensitivity to COµ.…”

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Development of Carotid Chemoreceptor Dynamic and Steady‐State Sensitivity to CO₂ in the Newborn Lamb

Calder

Kumar

Hanson

1997

The Journal of Physiology

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The maturation of carotid chemoreceptor steady‐state and dynamic responses to CO2 in newborn lambs was measured. In total, sixteen fibres (13 lambs) were studied at 3–4 days, nineteen fibres (13 lambs) at 5–9 days and twenty‐one fibres (17 lambs) at 10–24 days after birth. Steady‐state CO2 sensitivity was measured over a range of arterial CO2 pressures (Pa,CO2) at four levels of arterial O2 pressure (Pa,O2): hyperoxia (Hyp), 115–150 mmHg; normoxia (Nx), 90–105 mmHg; moderate hypoxia (ModHx), 40–60 mmHg; and severe hypoxia (SvHx), 20–35 mmHg. Steady‐state CO2 sensitivity was present at all ages, and a significant effect of age (P < 0.001) and Pa,O2 (P < 0.025) (ANOVA) was observed. Older lambs were unable to sustain an increase in chemoreceptor discharge during SvHx as CO2 was increased. Dynamic CO2 sensitivity was measured by producing alternations in end‐tidal CO2 levels (etCO2) (alternation amplitude, 1.23 ± 0.07% (mean ±s.e.m.); etCO2, 7.56 ± 0.15%) over 2–8 s at two Pa,O2 levels only: 80–100 (Nx) and 40–60 mmHg (ModHx). Peak and trough values of the oscillation in chemoreceptor discharge were plotted against maximum and minimum etCO2 for the control and CO2‐loaded breaths. Dynamic CO2 sensitivity was calculated as the slope between these points. Dynamic CO2 sensitivity was greater than steady‐state sensitivity in Nx (P < 0.05) and ModHx (P < 0.01, Student's paired t test). Unlike steady‐state CO2 sensitivity, there was no significant effect of age or Pa,O2 on dynamic sensitivity (P > 0.39 and P > 0.68, respectively, ANOVA). Our results show that the neonatal lamb possesses a carotid body steady‐state CO2 sensitivity within a few days of birth, an age when hypoxia sensitivity is low. This CO2 sensitivity increases with age, perhaps due to the increasing interaction between CO2 and O2. Dynamic sensitivity of the carotid body to CO2 is mature at birth and does not increase with age, as predicted if the response of the carotid body to rapid changes in CO2 is independent of the sensitivity to the partial pressure of O2 (PO2).

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confidence: 98%

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confidence: 98%

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confidence: 99%

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confidence: 99%

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Development of Carotid Chemoreceptor Dynamic and Steady‐State Sensitivity to CO₂ in the Newborn Lamb

Calder

Kumar

Hanson

1997

The Journal of Physiology

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Ventilatory response of the newborn infant to mild hypoxia

1997

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Effect of neonatal anoxia on the ventilatory response to hypoxia in developing rats

Saiki¹,

Matsumoto²

1999

Pediatr. Pulmonol.

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The purpose of the study was to determine whether an episode of anoxia in the neonatal period affects the hypoxic ventilatory response in developing rats. Three to 4 day old rats (EXP rats) (day 0 = day of birth) were exposed to 100% N2 for about 20 min. In anoxia, animals changed their respiratory movements to “gasping,” and were successfully autoresuscitated by placing them back into air. None of the EXP rats died after the resuscitation, and no differences were found between the EXP and control (CONT) rats in the somatic growth. The CONT rats were not exposed to anoxia during the neonatal period. On day 9–10(mean day 9) and days 23–29(mean day 25), ventilatory and metabolic responses to hypoxia (inspiratory oxygen fraction FiO2 = 10% on day 9; 15% and 10% on day 25) were compared in the EXP and CONT groups. On day 9, there were no differences in ventilatory and metabolic responses to hypoxia between the EXP and CONT groups. On day 25, 10% O2hypoxic ventilatory response (by the barometric method) was significantly higher in the EXP group than in the CONT group, as indicated by increases in both tidal volume (VT) and mean inspiratory flow (VT/TI). On the other hand, the metabolic effects were small, because metabolic rates (V′O2 and V′CO2, by a flow‐through method) were similar in both EXP and CONT groups under each gaseous condition. These results suggest that an episode of anoxia during the neonatal period has long‐lasting effects on the control of ventilation, including chemoreflexes, in rats. Pediatr Pulmonol. 1999; 28:313–320. © 1999 Wiley‐Liss, Inc.

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Carotid chemoreceptor response to natural stimuli in the newborn kitten

Cited by 68 publications

References 16 publications

Development of Carotid Chemoreceptor Dynamic and Steady‐State Sensitivity to CO₂ in the Newborn Lamb

Development of Carotid Chemoreceptor Dynamic and Steady‐State Sensitivity to CO₂ in the Newborn Lamb

Ventilatory response of the newborn infant to mild hypoxia

Effect of neonatal anoxia on the ventilatory response to hypoxia in developing rats

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Carotid chemoreceptor response to natural stimuli in the newborn kitten

Cited by 68 publications

References 16 publications

Development of Carotid Chemoreceptor Dynamic and Steady‐State Sensitivity to CO2 in the Newborn Lamb

Development of Carotid Chemoreceptor Dynamic and Steady‐State Sensitivity to CO2 in the Newborn Lamb

Ventilatory response of the newborn infant to mild hypoxia

Effect of neonatal anoxia on the ventilatory response to hypoxia in developing rats

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Product

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Development of Carotid Chemoreceptor Dynamic and Steady‐State Sensitivity to CO₂ in the Newborn Lamb

Development of Carotid Chemoreceptor Dynamic and Steady‐State Sensitivity to CO₂ in the Newborn Lamb