Microcirculatory effects of nicotine and related alkaloids.

To determine the effects of nicotine alkaloids on the microcirculation of a variety of tissues, we infused equimolar concentrations (10(-4)-10(-1) M) of 1-nicotine (N), nor-nicotine (NN), dihydro-metanicotine (DHN) in the skeletal muscle, in a skin flap chamber, and in a saline-perfused mesentery preparation of the rat (WistHan). The qualitative and quantitative responses to these equimolar concentrations were measured by modern microcirculatory techniques. Our data showed that 1-nicotine and its alkaloids differ significantly in dose-dependency, maximal vasoactivity, tissue specificity, and microvascular localization. In conclusion, the small differences in the chemical structure of the pyridine ring which distinguishes the alkaloids cause significantly different microvascular effects.