HALOPERIDOL DELAYS PATTERN ELECTRORETINOGRAMS MORE THAN VISUAL EVOKED-POTENTIALS IN NORMAL HUMANS - A PHARMACOLOGICAL TOOL IN PARKINSONS-DISEASE PATHOPHYSIOLOGY

1. Electroretinograms (ERG) and visual evoked potentials (VEP) by vertical grating pattern reversal stimulation were simultaneously recorded in healthy humans before and after haloperidol (23 subjects) or placebo (15 subjects) administration. Furthermore, 10 subjects received both treatments in two different sessions. 2. Haloperidol (0.05 mg/kg) produced a significant (P = 0.001) increase of ERG b-wave mean latency of about 7 ms, but did not significantly modify P100 latency. 3. Placebo administration did not alter any of the considered latencies. Similar results were obtained in the population which underwent the treatment twice. 4. We conclude that PERG is more sensitive than VEP to the pharmacological impairment of dopaminergic transmission and that b-wave latency should not be correlated to N75 or P100 in calculating the retino-cortical time.