Background & Aims : Unilateral Labyrinthectomy (UL) causes a syndrome of oculomotor, postural, and autonomic system disorders which diminish over time in a process of behavioral recovery known as vestibular compensation. Many studies have been done on the vestibular compensation after unilateral labyrinthectomy (UL) and regeneration of nerve cells, but the mechanism of vestibular compensation and regeneration nerve cells are not well known. The aim of this research was to study the effect of cobra venom on the vestibular compensation and regeneration of nerve cells of vestibular nuclei after damage of vestibular apparatus .

  Materials & Methods : The present experimental study was carried out on 20 adult male albino rat’s weight 230±30 gr. At first, the rats were randomly divided into dual groups include Normal, UL and, UL with NOX. Electrophysiological and histhochemically experiments were carried out on these groups. For electrophysiology assessment of paraventricular and supraoptic nuclei of hypothalamus were stimulated bipolar with high frequency stimulus 50 and 100 HZ during one second. The electrical activity of membrane cells of bilateral Dieters’ neurons on the form of titanic potanseation and depression were recorded. The end of electrophysiological experiment the brain stem rats were removed and put into solution of 5% neutral formalin for assessment of ca₂ depended acidic phosphates and after 48 hours for assessment of morphology was performed.

  Results: The increasing of inhibitory and excitatory reactions of Dieters’ neurons at early stage of vestibular compensation following NOX injection reaching the norm at late stage was revealed. In histochemical study after unilateral labyrenthectomy decrease in the activity of ca2-dependent acidic phosphates and chromotholysis, swelling of neurons were observed. The neurons look like degeneration pattern. But in the unilateral labyrinthectomy with NOX group, shape of cells was polygonal and smooth surface with high granulation. The pattern of cells was like norm cells.

  Conclusion : The cobra venom not only causes acceleration of vestibular compensation, but also causes regeneration of damage side of lateral vestibular nucleus neurons.

  SOURCE: URMIA MED J 2013: 24(9): 701 ISSN: 1027-3727