Kallidin und Bradykinin, vergleichende pharmakologische Untersuchungen

A COMPARISON OF THE EFFECTS OF THE PLASMA KININS, BRADYKININ AND KALLIDIN, ON MYOCARDIAL BLOOD FLOW AND METABOLISM

Using a heated thermocouple technique it was shown that the plasma kinins, kallidin (lys-bradykinin) and bradykinin, increased myocardial blood flow, when given either by single injection or by continuous slow infusion, in the rabbit, cat, dog, monkey and chimpanzee. In every experiment systemic arterial blood pressure and myocardial vascular resistance fell by an amount related to the log of the dose of the kinin administered. These effects were seen with quite small doses of bradykinin and kallidin and demonstrate that the myocardial vascular bed is very sensitive to these plasma kinins. In larger doses, bradykinin increased "corrected temperature" -the myocardial temperature change corrected for alterations in blood flow and with heat losses controlled. This response represents a stimulation of metabolic heat production which was not observed with kallidin.

Kinins in relation to kallikrein activity, kininogen, electrolytes, aldosterone and catecholamines in urine from normal individuals

The object of the present study was to test the hypothesis that urinary kinin excretion is an indicator of intrarenal kinin formation and to investigate urinary excretion of kinins in relation to natriuresis, kaliuresis, diuresis and urinary aldosterone and catecholamines in normal individuals on a free salt and water intake. In freshly voided urine collected from 24 normal individuals kinin concentration was directly related to kallikrein activity. Kininogen concentration was very low and neither related to kallikrein activity nor to kinin concentration. The excretion rates of kinins and kininogen were unrelated to the time interval between micturitions. In 24 hour urine collections from 50 normal individuals the excretion of kinins was positively correlated to natriuresis, kaliuresis and diuresis and also to dopamine but not to aldosterone, noradrenaline and adrenaline. Kinin excretion was inversely related to age and was lower in women than in men. On the basis of these results it is concluded that urinary kinin excretion reflects intrarenal kinin formation in normal ambulatory individuals and that urinary kinins are formed mainly in the interstitial and vascular space of the kidney. Furthermore, kinins and dopamine seem to play a physiological role in the renal handling of electrolytes and water.