Long-term potentiation and depression after unilateral labyrinthectomy in the medial vestibular nucleus of rats.
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 gamma-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.
Pettorossi
Vito Enrico
VE
Department of Internal Medicine, Section of Human Physiology, University of Perugia, Perugia, Italy. isfisuma@unipg.it
Dutia
Mayank
M
Frondaroli
Adele
A
Dieni
Cristina
C
Grassi
Silvarosa
S
D000222:Adaptation, Physiological; D000704:Analysis of Variance; D000818:Animals; D001933:Brain Stem / Q000502:physiology*; D046508:Culture Techniques; D004195:Disease Models, Animal; D007758:Ear, Inner / Q000601:surgery*; D004594:Electrophysiology; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D017774:Long-Term Potentiation; D008297:Male; D009473:Neuronal Plasticity; D013506:Otologic Surgical Procedures / Q000379:methods; D011336:Probability; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D014726:Vestibular Nuclei / Q000502:physiology*