Regional blood flow effects of ANP in conscious dogs: Preferential gastrointestinal vasoconstriction

R. L. Woods, J. J. Smolich

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Abstract

We studied total and regional blood flow responses to human atrial natriuretic peptide (α-hANP) using radioactive microspheres in six conscious dogs. Hemodynamic responses to infusions of α-hANP at 75 ng·kg-1·min-1 were determined in each dog in the presence and absence of autonomic reflexes using the ganglion blocking agent pentolinium. When autonomic reflexes were blocked, α-hANP caused a substantial reduction in gastrointestinal (GI) vascular conductance (35%) but had no significant effects in brain, kidneys, liver, skeletal muscle, or skin. This α-hANP-induced fall in GI conductance contributed more than 40% to the fall in total peripheral conductance (TPC) of 24% occurring after autonomic blockade. A fall in myocardial vascular conductance, most prominent in the left ventricle, contributed a further 40% to the fall in TPC. When autonomic reflexes were intact, α-hANP caused vasoconstriction in the GI region (29% fall in vascular conductance), had no significant effects on myocardial vascular conductance but significantly increased splenic vascular conductance. In addition to these systemic responses, α-hANP infusion also significantly reduced pulmonary vascular conductance, independent of autonomic reflex activity or changes in pulmonary artery pressure. Thus our results in conscious dogs demonstrate that α-hANP causes a systemic vasoconstriction, most pronounced in the GI region.

Original languageEnglish
JournalAmerican Journal of Physiology
Volume261
Issue number6 30-6
Publication statusPublished - 1991
Externally publishedYes

Keywords

  • Atrial pressure
  • Cardiac output
  • Myocardial blood flow
  • Pulmonary vascular conductance
  • Splanchnic blood flow

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