Vasodilator fibres to the tongue in the chorda tympani proper nerve.

Electrical stimulation of the chorda tympani proper nerve (CT) causes vasodilatation in the constant-flow perfused tongue. It has been suggested, as an explanation for this, that the vasodilatation is the result of antidromic impulses in sensory fibres of the CT. However, after degeneration of the efferent fibres in CT in the rat it was found that electrical stimulation of the CT caused no vasodilatation. Since, by all criteria available, the sensory fibres remained, the result indicates that antidromic impulses could not be the cause of the vasodiltation observed in tongues with intact nerve supply. Further, since there are no glands in the part of the tongue innervated by the CT and the circulation of the large salivary glands is separate from the tongue in the rat, it is concluded that the vasodilatation was not a secondary effect of glandular activity, but was caused by vasodilator fibres in the CT.