Long-term Potentiation and Depression after Unilateral Labyrinthectomy in the Medial Vestibular Nucleus of Rats

• Published in: Acta oto-laryngologica 2003-02, Vol.123 (2), p.182-186
• Main Authors: Pettorossi, Vito Enrico, Dutia, Mayank, Frondaroli, Adele, Dieni, Cristina, Grassi, Silvarosa
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Analysis of Variance; Animals; Biological and medical sciences; Brain Stem - physiology; Culture Techniques; Disease Models, Animal; Ear, Inner - surgery; Electrophysiology; Evoked Potentials, Auditory, Brain Stem; Female; Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics; long-term depression; Long-Term Potentiation; Male; Medical sciences; Neuronal Plasticity; Otologic Surgical Procedures - methods; Probability; Rats; Rats, Wistar; Sensitivity and Specificity; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the ear, the auditive nerve and the facial nerve; vestibular compensation; Vestibular Nuclei - physiology
• ISSN: 0001-6489; 1651-2251
• DOI: 10.1080/0036554021000028093

We previously demonstrated in rat brainstem slices that high-frequency stimulation (HFS) of the vestibular afferents induces long-term potentiation (LTP) in the ventral part (Vp) of the medial vestibular nucleus (MVN) and long-term depression (LTD) in the dorsal part (Dp). Both LTP and LTD depend on N-methyl-D-aspartate receptor activation, which increases synaptic efficacy; however, in the Dp, LTP reverses to LTD because of the activation of γ-aminobutyric acid-ergic neurons. Here we show that the probability of inducing long-term effects in the MVN of rat brainstem slices is altered after unilateral labyrinthectomy (UL). In fact, LTP occurs less frequently in the ventral contra-lesional side compared with sham-operated rats. In the dorsal ipsi-lesional side, LTD is reduced and LTP enhanced, while the opposite occurs in the dorsal contra-lesional side. These changes in synaptic plasticity may be useful for re-balancing the tonic discharge of the MVN of the two sides during vestibular compensation, and for enhancing the dynamic responses of the deafferented MVN neurons in the long term.