Saccadic eye velocity after selective GABAergic treatment with tiagabine in healthy volunteers.
BACKGROUND
Saccadic eye velocity (SEV) has been shown to be a reliable neurophysiological tool for the assessment of gamma-aminobutyric acid GABA(A) receptor sensitivity. Administration of benzodiazepines targeting the GABA(A) receptor decreases SEV in healthy volunteers. Tiagabine is a new antiepileptic drug which acts via selective blockade of GABA reuptake. Therefore, we examined the effects of tiagabine on saccade parameters.


METHODS
SEV was analyzed in 8 healthy volunteers before and after 7 days of tiagabine treatment. Subjects received tiagabine in a daily dose of 15 mg. Saccades were measured using a noninvasive infrared oculographic device. Amplitude, latency, and SEV were analyzed as a function of treatment and target eccentricity.


RESULTS
SEV and saccade latency increased with target amplitude. Treatment with tiagabine had no significant effect on SEV and saccade amplitude. A trend was found for increased latencies after tiagabine.


CONCLUSIONS
In contrast to findings with benzodiazepines, tiagabine treatment had no impact on SEV in healthy volunteers. The subchronic tolerance effects or the different site of action on the GABA(A)/BZD receptor complex may account for this deviating profile.
Zwanzger
Peter
P
Department of Psychiatry, University of Munich, Nussbaumstrasse 7, DE-80336 Munich, Germany. zwanzger@med.uni-muenchen.de
Schule
Cornelius
C
Eser
Daniela
D
Baghai
Thomas C
TC
Padberg
Frank
F
Ella
Robin
R
Moller
Hans-Jürgen
HJ
Rupprecht
Rainer
R
Kathmann
Norbert
N
D000328:Adult; D005260:Female; D018755:GABA Agonists / Q000097:blood / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009557:Nipecotic Acids / Q000097:blood / Q000494:pharmacology*; D011963:Receptors, GABA-A / Q000187:drug effects; D012438:Saccades / Q000187:drug effects*; D000078308:Tiagabine; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018755:GABA Agonists; D009557:Nipecotic Acids; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D000078308:Tiagabine