Abstract
1. The isometric and isotonic response of strips of sheep's carotid artery to varying concentrations of adrenaline are shown to agree satisfactorily with the formula
[See formula in the PDF File]
where x = concentration, y = action as per cent of maximum action (A), and K = constant.
2. When the frog's aorta is perfused with varying concentrations of adrenaline the relation between concentration and out-flow approximates to the formula given above over a wide range of concentrations. This partial coincidence is surprising because when the pressure is constant the outflow from a tube varies as (radius)4.
3. The relations between dosage of adrenaline and rise of blood pressure in the pithed cat follows the formula given above. This agreement is partly explained by the fact that the relation between adrenaline dosage and increase in cardiac frequency follows the formula fairly exactly.
4. An important consequence of the relation that has been shown to exist between the concentration of adrenaline and the action it produces is that when physiological concentrations are present the effect produced varies almost directly as the concentration, whereas when higher toxic concentrations are present, the effect varies as the logarithm of the concentration.
Footnotes
- Received February 3, 1928.
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