Effects of oral pH on cigarette smoking

Permeability of nicotine across the oral mucosa had been shown to be a direct linear function of alkalinity in the oral cavity. Here, oral pH in cigarette smokers was manipulated from pH 5 to 8 by rinses with Sorenson's and McIlvaine's buffers. As a alkalinity increased, cigarette taste was perceived as stronger, more bitter, and, in some cases, more upleasant; and heart-rate accelerated slightly. Nicotine self-administration and blood pressure were not influenced. Differential absorption of nicotine and cross-adaptation of sour to bitter taste are both discussed as explanations for the results.