POLYAMINES IN THE LATERAL VESTIBULAR NUCLEI OF THE SQUIRREL-MONKEY AND THEIR POTENTIAL ROLE IN VESTIBULAR COMPENSATION

Polyamine synthesis increases in response to injurious stimuli includi ng axotomy and denervation. Reduced eye nystagmus and head-deviation h ave been observed in unilateral labyrinthectomized (UL) guinea pigs tr eated with an inhibitor of polyamine synthesis, alpha-difluoromethylor nithine (DFMO). We quantified polyamines in the lateral vestibular nuc lei (LVN) of control and UL squirrel monkeys during the phase of vesti bular compensation (VC) and performed an experiment to determine if DF MO reduces nystagmus previously observed in the guinea pig. Polyamines were detected in the LVN of control and UL squirrel monkeys. Putresci ne and spermidine increased in the ipsilateral LVN 3 days after UL wit h no change in the contralateral LVN. No left-right differences were n oted in the 5-day post-UL monkey. DFMO reduced nystagmus in a UL squir rel monkey. These findings suggest that polyamines are important in ve stibular function and may contribute to nystagmus observed in VC.