The effect of the potassium channel blocker 4-aminopyridine(4-AP) on spontan eous upbeat nystagmus (UBN) was investigated with the search coil technique duri ng fixation in different gaze positions and smooth pursuit ...The effect of the potassium channel blocker 4-aminopyridine(4-AP) on spontan eous upbeat nystagmus (UBN) was investigated with the search coil technique duri ng fixation in different gaze positions and smooth pursuit in a patient before a nd after ingestion of 10 mg 4-AP. UBN was reduced from 8.6 deg/s to 2.0 deg/s b y 4-AP causing subjective relief from distressing oscillopsia, and impaired upw ard smooth pursuit was restored(gains: before medication 0.38; after medication 0.86). In the dark, UBN was slightly stronger and not affected by 4-AP. We prop ose that 4-AP improved the function of cerebellar pathways that mediate gaze ho lding and smooth pursuit by intensifying the excitability of cerebellar Purkinje cells.展开更多
文摘The effect of the potassium channel blocker 4-aminopyridine(4-AP) on spontan eous upbeat nystagmus (UBN) was investigated with the search coil technique duri ng fixation in different gaze positions and smooth pursuit in a patient before a nd after ingestion of 10 mg 4-AP. UBN was reduced from 8.6 deg/s to 2.0 deg/s b y 4-AP causing subjective relief from distressing oscillopsia, and impaired upw ard smooth pursuit was restored(gains: before medication 0.38; after medication 0.86). In the dark, UBN was slightly stronger and not affected by 4-AP. We prop ose that 4-AP improved the function of cerebellar pathways that mediate gaze ho lding and smooth pursuit by intensifying the excitability of cerebellar Purkinje cells.