The effects of nicotine on laser Doppler measures of cochlear blood flow.

Anesthetized guinea pigs were given arterial bolus injections of saline or varying nicotine concentrations. Blood flow through the cochlea and skin were measured via laser Doppler and arterial blood pressure via an arterial cannula. Cochlear blood flow increased with low doses of nicotine but decreased with the highest dose, while blood pressure increased and skin flow decreased with all doses of nicotine. Control injections of saline vehicle had only minor and transient effects.