[Anatomical study of rat trigeminal motor nucleus-lateral pterygoid muscle projection pathway].

To determine the opening and closing action of the external muscle, the projection pathway of the axon terminal of trigeminal motor nucleus (Vmo) neuron to the lateral pterygoid muscle was revealed. In this study, 10 SD rats of 8 weeks old were included. The left lateral pterygoid muscle of SD rats was surgically exposed, and the wound was closed after intramuscular injection of hydroxystilbamidine/fluorogold (FG) 3-5 μl. Seven days after the operation, the experimental animals were perfused, samples collected and sectioned for immunofluorescence staining. After FG injection into the lateral pterygoid muscle, the FG reversed in the Vmo neurons. In the Vmo neurons on the FG injection side (left side), a large number of FG reversed neurons were found in the corpus luteum and dendrites. These neurons were not only distributed in the dorsolateral part of the trigeminal motor nucleus that innervated the closed muscle, but also in the ventral medial portion of the trigeminal nucleus of the open muscle. The neuronal conduction pathway between the Vmo and the lateral pterygoid muscle innervates the lateral pterygoid muscle. The neurons are distributed both in the dorsolateral and in the nucleus of the ventral ventricle. It is concluded that the lateral pterygoid muscle involve in the jaw closing and opening movement.