Abstract
Abstract: :
Purpose: It has been reported that adenosine, a small naturally occurring molecule, exerts a trophic effect on cultured brain cells (Lee et. al, PNAS 98:3555, 2001). The purpose of this study was to determine whether adenosine and related agonists have survival effects on cultured retinal ganglion cells (RGCs). Methods: RGCs were purified from dissociated rat retinal cells (postnatal day 6) by a modified two-step panning method (Otori, IOVS, 1998) and seeded on poly-L-lysine- and laminin-coated glass coverslips in neurobasal medium containing B27, glutamine and forskolin (the "basal medium"). Adenosine (10 and 100 µM), A2a receptor agonist CGS-21680 (2.5, 10 and 100 nM ), BDNF (40 ng/mL) or combination of BDNF, CNTF and bFGF (each of 40 ng/mL) was added to the basal medium. After 3 days of cultivation, viability of RGCs was determined by calcein-acetoxymethyl ester staining. Results: Treatment with 100 µM of adenosine increased the number of viable RGCs by 1.8-fold compared to those cultivated in the basal medium. Similar effects were also observed with 10 and 100 nM of CGS-21680 in a dose-dependent manner. Treatments with BDNF and combination of neurotrophic factors resulted in 2.1 and 3.7-fold increases, respectively. Conclusions: These results suggest that adenosine promotes the survival of RGCs in the absence of neurotrophic factors by stimulating A2a receptors.
Keywords: adenosine • ganglion cells • neuroprotection