Journal of Ophthalmology

Research Article

Retinal Electrophysiology Is a Viable Preclinical Biomarker for Drug Penetrance into the Central Nervous System

Table 1

Summary of GABAa agonist effects on the ERG and VEP in conscious and anaesthetised rats.
 IM isoguvacineIV isoguvacineICV isoguvacineIM muscimolIV muscimolICV muscimol
 Consciousket : xylConsciousket : xylConsciousket : xylConsciousket : xylConsciousket : xylConsciousket : xyl
(A) ERG parameters            
 Photoreceptor amplitude—↓——  —↓——  
 Rod bipolar cell amplitude—↓—↑  —↓—↓  
 Cone amplitude—↓↓↓  ↓↓↓↓  
 Photoreceptor sensitivity————  —↓——  
 Rod bipolar cell sensitivity———↑  ↑↑↑↑  
 Cone bipolar implicit time———↑  —↑—↑  
(B) VEP parameters            
 P1-N1 amplitude——  —↓↑↑  ↑↓
 P2-N1 amplitude——  —↓↑—  ↑—
 N1 time——  —↑↑↑  —↑
 P2 time——  ↑———  ——
Arrows indicate the direction of effect compared to relevant baseline (conscious or anaesthetised); dashes indicate no significant effect. IM: intramuscular; IV: intravitreal; ICV: intracerebroventricular.