The effect of hyperventilation on maternal placental blood flow in pregnant rabbits

Leduc, Bernard

doi:10.1113/jphysiol.1972.sp009943

Cited by 34 publications

(14 citation statements)

References 11 publications

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“…Only mean arterial pressure and blood flow to the stomach fell significantly. These observations agree with those of Duncan (1969) and Leduc (1972) who found that the injection of microspheres 30-45 min apart in anaesthetized pregnant rabbits had little effect on cardiac output or its distribution. There were no significant changes in blood gas values, heart rate, or total peripheral resistance.…”

Section: Validationsupporting

confidence: 92%

THE USE OF RADIOACTIVE MICROSPHERES TO COMPARE THE EFFECTS OF HYDRALAZINE, GUANETHIDINE AND SK&F 24260 ON THE REDISTRIBUTION OF CARDIAC OUTPUT IN ANAESTHETIZED RABBITS

Johnston

1975

British J Pharmacology

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IThe use of radioactive microspheres is described for the measurement of cardiac output in anaesthetized rabbits and its redistribution after the administration of drugs which lower blood pressure.2 Hydralazine increased peripheral vascular conductance by 123%. The vascular beds in which it had most effect were those of the carcass (mainly muscle) and the kidneys. 3 SK&F 24260,(1,4 dihydro-2, 6-dimethyl-4-(2-trifluormethylphenyl)-3,5,-pyridinedicarboxylic acid diethyl ester), had similar vasodilator actions. Its effect in the carcass contributed relatively more to the increase of total peripheral conductance. It also caused a remarkable degree of cerebral vasodilatation. 4 Guanethidine had a relatively small effect on total peripheral conductance and lowered blood pressure mainly by reducing stroke volume and cardiac output.

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Section: Validationsupporting

confidence: 92%

THE USE OF RADIOACTIVE MICROSPHERES TO COMPARE THE EFFECTS OF HYDRALAZINE, GUANETHIDINE AND SK&F 24260 ON THE REDISTRIBUTION OF CARDIAC OUTPUT IN ANAESTHETIZED RABBITS

Johnston

1975

British J Pharmacology

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“…The increase in uterine blood flow following maternal hypercapnia in sows is complementary to the findings of Leduc (1972). Working with rabbits, he noted a decrease in maternal placental blood flow, when maternal PcO, levels were decreased to approximately 18 mmHg by hyperventilation.…”

Section: Inhalation Of 100 % Oxygenmentioning

confidence: 78%

The effects of maternal hypercapnia on foetal oxygenation and uterine blood flow in the pig.

Hanka¹,

Lawn²,

Mills³

et al. 1975

The Journal of Physiology

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SUMMARY1. The purpose of this investigation was to determine the effects of maternal hyperoxaemia and hypercapnia on the uterine vascular bed and foetal oxygenation in the large white sow at 80-90 days gestation.2. When maternal hyperoxaemia was induced with 100 % oxygen, there was a highly significant rise in the maternal arterial oxygen tension, but no other significant blood gas or vascular changes were observed.3. When mild maternal hypercapnia was superimposed on maternal hyperoxaemia (oxygen plus 6 % carbon dioxide), the oxygen tension and saturation of both the maternal uterine venous and foetal umbilical venous bloods were significantly increased. Similar but more pronounced increases were found when severe hypercapnia was induced (oxygen plus 50 % carbon dioxide) but in this case all blood samples showed dramatic changes in Pco, and pH. These changes were accompanied by an increase in the systemic blood pressure and uterine blood flow, and a decrease in uterine vascular resistance. 4. When mild hypercapnia was induced without hyperoxaemia (air plus 5 % carbon dioxide) significant increases were recorded in the oxygen tension and saturation of uterine venous and foetal umbilical venous bloods. Systemic and uterine arterial blood pressure rose, the uterine blood flow increased, and uterine vascular resistance fell. 5. It was concluded that the increased foetal oxygen tension during maternal hypercapnia was the result of the increased uterine blood flow and greater mass delivery of oxygen to the placenta, so that once the oxygen requirements of the placental tissues themselves were exceeded there would be an increased oxygen gradient at the site of gas exchange.

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“…However, in late-pregnant animals, placental blood flow is maximum (Ahokas, Anderson & Lipshitz, 1983) and must be maintained in order to constantly supply oxygen and nutrition to the fetus. It has been reported that the intravenous injection of noradrenaline induces maternal placental vasoconstriction (Leduc, 1972). Thus, increase of noradrenaline in the blood induced by cold exposure might be dangerous for a fetus.…”

Section: Discussionmentioning

confidence: 99%

Suppression of cold‐induced thermogenesis in full‐term pregnant rats.

Imai-Matsumara

Matsumura

Morimoto

et al. 1990

The Journal of Physiology

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SUMMARY1. Thermoregulation against cold exposure was studied in rats during pregnancy and early lactation, and compared with that of virgin rats.2. When exposed to 0 TC for 60 min, rats which were within 24-48 h of parturition (pre-1-day rats) and those within 24 h of parturition (pre-0-day rats) showed significantly larger falls of colonic temperature (To) than virgin rats. The temperature decrease was greatest in the pre-0-day rats, being 4' 1 + 0 4 0C (mean + S.E.M.) at the end of cold exposure, compared with a decrease of 1-7 + 0-3 0C in the virgin rats. The tail skin temperature fell to 0 0C during cooling in all virgin rats and in pregnant rats at each gestational stage.3. During cold exposure at 10 0C for 30 min, pre-0-day rats also showed significantly larger falls in Tco (1I8+006 'C) than virgin (0-4+0-2 'C), pre-1-week (0-8 + 0 3 0C), post-0-day (0 3 + 0 3 0C) or post-I -week rats (0 4 + 0 3 0C). Although body weights in pre-0-day rats were far larger than those in virgin rats, the increase in oxygen consumption per animal during cold exposure was 50 % lower in pre-0-day rats (2-2 + 0 5 ml/min) than in virgin rats (5 3 + 0-3 ml/min). There was no difference in basal oxygen consumption per animal between the late pregnant and virgin rats.4. Within 24 h after parturition, both the decrease of Tco and the increase of oxygen consumption during cold exposure returned to the values observed in virgin rats.5. The present results demonstrate clearly that cold-induced thermogenesis is significantly suppressed in rats at a late stage of pregnancy.

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The effect of hyperventilation on maternal placental blood flow in pregnant rabbits

Cited by 34 publications

References 11 publications

THE USE OF RADIOACTIVE MICROSPHERES TO COMPARE THE EFFECTS OF HYDRALAZINE, GUANETHIDINE AND SK&F 24260 ON THE REDISTRIBUTION OF CARDIAC OUTPUT IN ANAESTHETIZED RABBITS

THE USE OF RADIOACTIVE MICROSPHERES TO COMPARE THE EFFECTS OF HYDRALAZINE, GUANETHIDINE AND SK&F 24260 ON THE REDISTRIBUTION OF CARDIAC OUTPUT IN ANAESTHETIZED RABBITS

The effects of maternal hypercapnia on foetal oxygenation and uterine blood flow in the pig.

Suppression of cold‐induced thermogenesis in full‐term pregnant rats.

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