The invention relates to a movable vane of a turbomachine comprising a blade (12) with inner cooling cavities and a root (11) by which means the vane can be mounted on a rotor disk, the root comprising at least two channels (11a) communicating with said inner cavities and leading to the base (11b) thereof, said base comprising at least two openings (11b1, 11b2) through which the channels open up, and a calibrating plate (20) provided with calibrated perforations (21, 22) corresponding to said openings being attached to the base (11b) of the root. The vane is characterized in that a mechanical means (25, 26; 11m1, 11m2) forming a sealing barrier between the two openings is arranged between the plate and the base of the root.