Effect of codeine on rat and guinea pig tracheal ciliary beat frequency.

Codeine, the basic antitussive drug, has generally been thought to impair mucociliary function. Using the photodetection method the effect of codeine on mucociliary function was studied in rat after local and systemic administration and in guinea pig after systemic administration. In vitro rat tracheal ciliary beat frequency (CBF) was measured up to 40 min. There was 24.6 +/- 2.5% and 26.6 +/- 1.6% decrease in CBF after 1 mg/ml and after 10 mg/ml codeine solutions, respectively. In vivo codeine was administered in single i.v. doses of 10 and 15 mg/kg. No statistically significant differences were found in CBF responses, although there was a CBF decreasing tendency after the 15 mg/kg dose. The total follow-up time was 120 min. In guinea pig, 10 days s.c. codeine administration in daily doses of 3, 10 and 30 mg/kg had no effect on CBF. Although codeine was used in much higher concentrations than tissues concentrations after therapeutic doses of codeine, the effects on CBF were minimal. So it can be concluded that the generally accepted ciliostatic effect of codeine is overestimated.

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.