Effects of intravenous ATP on tracheal ciliary activity, airway resistance and haemodynamics in rats.

The effect of the intravenous administration of ATP on the airway ciliary beating frequency (CBF) of anaesthetized rat was studied by measuring CBF photoelectrically from the inner surface of incised trachea. ATP (1 or 10 mg/kg) caused no changes in the CBF, but the decrease in CBF, which was seen after 70 min. in control rats, was abolished by ATP (10 mg/kg). ATP acutely decreased blood pressure; at 10 mg/kg, the decrease was 70 mmHg in systolic, and 60 mmHg in diastolic blood pressure. ATP also tended to increase rectal temperature and airway resistance, but these effects were not significant. ECG remained normal. Intravenous administration of ATP helps to maintain the function of tracheal cilia in anaesthetized rats at doses that, although lower blood pressure, do not cause fatal untoward effects.