Abstract
Purpose: :
To study changes in retinal function after cocaine exposure in adult rats, and the capacity of topiramate to prevent these changes, respectively.
Methods: :
Animals were treated in accordance to the ARVO statement for the use of animals in ophthalmic and vision research. Male Wistar rats, 270 g body weight (Charles River S.A., Barcelona, Spain), were used. Animals were divided into two groups (n = 8) as required by the experiment (control and cocaine). Cocaine (Sigma Química, Alcobendas, Madrid, Spain) was daily administered by intraperitoneal injection at a dose of 15mg/Kg in saline during 18 days. Control animals were injected with the same saline volume. Then, control group was subdivided into two subgroups (control and control-topiramate), and cocaine group was subdivided into two subgroups (cocaine, cocaine-topiramate) as well. Topiramate (Topamax® 10mg/Kg) was daily administered orally by stomach tube to the corresponding groups, while animals without topiramate received the same saline volume during others 18 days. Rats were sacrificed on day 36. Prior to sacrifice electroretinogram (ERG) an visual evoked potentials (VEP) were measured with the rats previously anesthetized and adapted to darkness overnight.
Results: :
Treatment with cocaine induced no changes in the a-wave implicit time. However, cocaine consumption induced a decreased in a-wave ERG amplitude respect to control and control-topiramate values. This change was prevented by the administration of topiramate. Cocaine treatment did not impair b-wave ERG implicit time. Moreover, b-wave amplitudes showed no change in any groups respect to control group. Finally, neither the implicit time of the VEP nor the amplitude of the VEP was altered by cocaine treatment in any of the groups studied.
Conclusions: :
Topiramate can be an effective treatment to prevent the damage induced by cocaine abuse in the retina, though further studies are needed.
Keywords: electroretinography: non-clinical • retina • pathology: experimental