Effect of nicotine on isolated human blood vessels

The action of nicotine was studied in isolated human vascular strip preparations using isometric recording of tension. Nicotine per se did not elicit any significant changes of smooth muscle tone. The effect of noradrenaline and direct smooth muscle stimulation, however, was enhanced. This action presumably is not dependent upon an adrenergic nervous mechanism, as in the intact organism but seems to be dependent upon a direct smooth muscle stimulation in itself not sufficiently strong to induce a contraction but leading to facilitated stimulation and propagation of the response.