The effects of acetazolamide on the electroretinographic responses in rats.
OBJECTIVE
To study the mechanisms and sites of action of the carbonic anhydrase inhibitor, acetazolamide (AZM), on the rod- and cone-mediated electroretinogram (ERG) of the dark-adapted rat.


METHODS
After a within-subjects design, ERG responses to brief, full-field flashes were recorded from adult (60 to 90 days old) albino rats, with and without AZM (5 mg/100 g, intraperitoneally). Flickering stimuli (6 and 26 Hz) were used to study rod- and cone-mediated responses. Aspartate-isolated responses of the isolated retina were recorded with and without AZM in the superfusate. The a-wave and PIII responses were fitted with a model of the rod's response by estimating the maximum response (Rmp3), sensitivity (S), and delay td. The b-wave response amplitude and implicit time were examined as a function of stimulus energy. The parameters obtained in the AZM-treated and untreated conditions were compared.


RESULTS
Acetazolamide causes a significant decrease in saturated rod response, b-wave amplitude, aspartate-isolated PIII, and the rod- and cone-mediated responses to flickering light. The estimated sensitivity of the rod response (S), b-wave sensitivity, and b-wave implicit time are not altered significantly by AZM.


CONCLUSIONS
Acetazolamide, probably through mechanisms that acidify the retina, attenuates the amplitudes of the retinal responses without significant effect on sensitivity.
Findl
O
O
Department of Ophthalmology, Children's Hospital, Boston, Massachusetts, USA.
Hansen
R M
RM
Fulton
A B
AB
D000086:Acetazolamide / Q000494:pharmacology*; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D003623:Dark Adaptation; D004596:Electroretinography / Q000187:drug effects*; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects
D001224:Aspartic Acid; D000086:Acetazolamide