Reflex discharge evoked by water stimulation on the frog tongue.

The frog tongue contains the chemoreceptor sensitive to water, the role of which has not been clarified. If the water on the tongue reflexly keeps the mouth closed as suggested by Zotterman, reflex discharges should be evoked in the nerve innervating the mandible elevator muscles. So far as we have studied, however, pronounced reflex discharges were evoked in the nerve innervating the submental and submaxillary muscles, but not in the nerves innervating the elevator muscles. This result suggests that the chemoreceptor sensitive to water in the frog tongue plays a role in the nostril closing mechanism.