Dieterich M, Straube A, Brandt T, Paulus W, Büttner U. The effects of baclofen and cholinergic drugs on upbeat and downbeat nystagmus.
J Neurol Neurosurg Psychiatry 1991;
54:627-32. [PMID:
1654396 PMCID:
PMC1014435 DOI:
10.1136/jnnp.54.7.627]
[Citation(s) in RCA: 97] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The GABAergic drug baclofen and the cholinergic drug physostigmine were administered to patients with upbeat and downbeat nystagmus. Baclofen (orally, 5 mg three times daily) reduced nystagmus slow phase velocity and distressing oscillopsia by 25-75% in four out of five patients (two upbeat nystagmus; two downbeat nystagmus). Physostigmine (1 mg single intravenous injection) increased nystagmus in five additional patients with downbeat (1) or positional downbeat nystagmus (4) for a duration of 15-20 minutes. The different interactions of baclofen and physostigmine on neurotransmission subserving vertical vestibulo-ocular reflex could account for these effects. The response to baclofen appears to be a GABA-B-ergic effect with augmentation of the physiological inhibitory influence of the vestibulo-cerebellum on the vestibular nuclei. Similarly baclofen has an inhibitory effect on the velocity storage mechanism. Cholinergic action may cause the increment of nystagmus by physostigmine.
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