Effect of Topical Anesthetics on Ciliary Activity of Chicken Embryo Tracheal Organ Cultures

Because of conflicting reports concerning the effect of topical anesthetics on cilia, testing of four different agents was undertaken. The agents were hexylcaine 5% (Cyclaine®), tetracaine 2% (Pontocaine®), cocaine 5% and 10%, and lidocaine 4% (Xylocaine®). Tracheas were removed from 19 to 20 day old chicken embryos. Ciliary activity was graded as to extent and vigor. Two methods of testing were used. In the first, dilutions of each agent were made, and tracheal rings were placed in the wells of microtiter plates and completely covered with the test drug. In the second method of testing, 0.8 ml of the test drug was injected in vivo into the exposed trachea of the embryo. In immersion testing, cilia stopping effect (CSE) in tracheal rings was noted in all drug dilutions tested within 1 to 20 minutes. When the drug was injected directly into the trachea, a complete CSE was noted the next day in the rings from the tetracine and hexylcaine injected tracheas. Three days following in vivo transtracheal injection of lidocaine and cocaine, ciliary activity in these and the control rings was similar. Although cilia did not tolerate total immersion in any of the agents tested, ciliary activity in tracheas injected with lidocaine and cocaine did not differ significantly from the control tracheal rings. Physicians who use topical anesthetics should be aware of this.