Effects of acid base changes upon the chronotropic response to norepinephrine

M. C. Camilion de Hurtado; O. A. Gende; H. E. Cingolani

Effects of acid base changes upon the chronotropic response to norepinephrine

M. C. Camilion de Hurtado, O. A. Gende, H. E. Cingolani

Research output: Contribution to journal › Article › peer-review

Abstract

The effect of changes in pH produced by changing NaHCO₂ at constant pCO₂ and by changing pCO₂ at constant NaHCO₂ concentration was studied in the spontaneous beating rat atrium. Alkalosis produced either by changes in pCO₂ or in NaHCO₂ concentration increased basal heart rate shifting dose response curves to norepinephrine upwards. When these dose response curves were analysed for a horizontal shift, it was found that the necessary dose to produce a given effect was lesser in alkalosis than in acidosis. This shift was significant at the ED₁₀ and at ED₃₀ when the pCO₂ was lowered and at ED₃₀, ED₅₀ and ED₇₀ when the NaHCO₂ concentration was increased. β adrenergic blockade did not prevent the rate increasing effect of alkalosis. The results suggest that there is a sensitizing effect to norepinephrine in alkalosis superimposed to a direct effect of pH upon heart rate.

Original language	English (US)
Pages (from-to)	120-127
Number of pages	8
Journal	Acta Physiologica Latino-Americana
Volume	25
Issue number	2
State	Published - 1975
Externally published	Yes

ASJC Scopus subject areas

Physiology
Pharmacology

Cite this

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title = "Effects of acid base changes upon the chronotropic response to norepinephrine",

abstract = "The effect of changes in pH produced by changing NaHCO2 at constant pCO2 and by changing pCO2 at constant NaHCO2 concentration was studied in the spontaneous beating rat atrium. Alkalosis produced either by changes in pCO2 or in NaHCO2 concentration increased basal heart rate shifting dose response curves to norepinephrine upwards. When these dose response curves were analysed for a horizontal shift, it was found that the necessary dose to produce a given effect was lesser in alkalosis than in acidosis. This shift was significant at the ED10 and at ED30 when the pCO2 was lowered and at ED30, ED50 and ED70 when the NaHCO2 concentration was increased. β adrenergic blockade did not prevent the rate increasing effect of alkalosis. The results suggest that there is a sensitizing effect to norepinephrine in alkalosis superimposed to a direct effect of pH upon heart rate.",

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AU - Camilion de Hurtado, M. C.

AU - Gende, O. A.

AU - Cingolani, H. E.

PY - 1975

Y1 - 1975

N2 - The effect of changes in pH produced by changing NaHCO2 at constant pCO2 and by changing pCO2 at constant NaHCO2 concentration was studied in the spontaneous beating rat atrium. Alkalosis produced either by changes in pCO2 or in NaHCO2 concentration increased basal heart rate shifting dose response curves to norepinephrine upwards. When these dose response curves were analysed for a horizontal shift, it was found that the necessary dose to produce a given effect was lesser in alkalosis than in acidosis. This shift was significant at the ED10 and at ED30 when the pCO2 was lowered and at ED30, ED50 and ED70 when the NaHCO2 concentration was increased. β adrenergic blockade did not prevent the rate increasing effect of alkalosis. The results suggest that there is a sensitizing effect to norepinephrine in alkalosis superimposed to a direct effect of pH upon heart rate.

AB - The effect of changes in pH produced by changing NaHCO2 at constant pCO2 and by changing pCO2 at constant NaHCO2 concentration was studied in the spontaneous beating rat atrium. Alkalosis produced either by changes in pCO2 or in NaHCO2 concentration increased basal heart rate shifting dose response curves to norepinephrine upwards. When these dose response curves were analysed for a horizontal shift, it was found that the necessary dose to produce a given effect was lesser in alkalosis than in acidosis. This shift was significant at the ED10 and at ED30 when the pCO2 was lowered and at ED30, ED50 and ED70 when the NaHCO2 concentration was increased. β adrenergic blockade did not prevent the rate increasing effect of alkalosis. The results suggest that there is a sensitizing effect to norepinephrine in alkalosis superimposed to a direct effect of pH upon heart rate.

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Effects of acid base changes upon the chronotropic response to norepinephrine

Abstract

ASJC Scopus subject areas

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