title: Cardiac substances that influence blood-pressure. II. Potent pressor activity in rat and rabbit atrial muscle.
abstract: In addition to their natriuretic, diuretic and vasodilator activities, freshly prepared aqueous extracts of either rat or rabbit atrial myocardium were shown to elicit significant increases in the blood-pressure of anaesthetized rats. Small aliquots (0.05 ml) intravenously administered caused a transient rise in mean arterial blood-pressure of up to 20%. Slow infusion of 0.4 ml right atrial extract (corresponding to about one half of a rabbit right atrial lobe) during 90 seconds caused the expected natriuresis and diuresis, together with a sustained elevation in arterial blood-pressure (ca 25%) that returned to normal within 3 minutes. This potent pressor activity could not be detected in ventricular extracts. It was furthermore readily separable from the natriuretic peptides and catecholamines by ultrafiltration. The atrial pressor factor is a small proteolytically unstable molecule (300-1000 dalton).
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D006325:Heart Atria / Q000032:analysis; D008297:Male; D008970:Molecular Weight; D009206:Myocardium / Q000032:analysis*; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D014020:Tissue Extracts / Q000494:pharmacology
chemical_list: D014020:Tissue Extracts