Summary
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1.
In unanesthetized toads,Bufo arenarum Hensel, intermittent increases of blood pressure and heart rate were invariably observed when spontaneous breathing increased. When blood pressure reached its maximum the polypnea stopped abruptly and both heart rate and blood pressure declined slowly to their previous values.
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2.
Sensory stimulation also evoked polypnea followed by hypertension and tachycardia.
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3.
In the anesthetized animal, artificial lung inflation increased left atrial and mean blood pressure proportionally to the volume of air injected. Similar results were obtained when coelomic instead of lung pressure was increased. In all cases a simultaneous tachycardia was observed.
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Neither autonomic blockade nor removal of the bulbomesencephalic centres abolished these responses.
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5.
It is concluded that these pressor and chronotropic effects of breathing are dependent on direct as well as on reflex mechanisms consequent to both coelomic and lung pressure changes. Direct effect of pulmonary venous return (or lower CNS mechanical reflexes) may be important in the intact animal.
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This work was supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas
Established Investigator of the Consejo Nacional de Investigaciones Cientifícas y Técnicas
Fellow of the Consejo Nacional de Investigaciones Cientificas y Técnicas
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Segura, E.T., Bronstein, A. & Schmajuk, N.A. Effect of breathing upon blood pressure and heart rate in the toad,Bufo arenarum Hensel. J Comp Physiol B 143, 223–227 (1981). https://doi.org/10.1007/BF00797701
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DOI: https://doi.org/10.1007/BF00797701