Figure 1
From: Oral administration of inosine produces antidepressant-like effects in mice
Inosine promotes neuronal viability and neurite outgrowth.
Neocortical neurons were incubated with inosine for one day. (a) Surviving neurons stained with CBB. Scale bar: 20 μm. (b, c) Dose-dependent effect of inosine on cell viability. Surviving neurons were counted under a microscope (n = 5) (b). Viability was measured by a colorimetric method with water-soluble tetrazolium compound (n = 4) (c). (d), (e) Dose-dependent effect of inosine on neurite outgrowth. After staining with CBB, the number of cells bearing neurites (d) and that of cells extending neurites longer than the soma (e) was counted (n = 5). *P < 0.05, **P < 0.01, versus 0 μM of inosine. (f) Effect of transient treatment with inosine on neuronal viability. Two hours after the addition of 100 μM inosine, neurons were washed with fresh medium and further incubated for one day. Surviving neurons were counted (n = 6). **P < 0.01, versus 0 μM of inosine. (g) Inhibitory effects of adenosine receptor antagonists on neurotrophic function of inosine. CPT or CSC (10 μM) was added to neurons 1 hour before supplementation of 100 μM inosine. One day after the incubation, surviving neurons were counted (n = 5). **P < 0.01, versus 0 μM of inosine, inosine + CPT and inosine + CSC, respectively. (h–j) Inosine-induced phosphorylation of MAPK in neurons. Dose-dependent phosphorylation of MAPK was determined in neurons 10 min after supplementation of the indicated amount of inosine. Adenosine was used as a positive control (n = 3) (h). For time course analyses, neurons were harvested at 5, 10 and 20 min after supplementation of inosine (n = 3) (i). CPT or CSC (1 μM) was added to neocortical neurons 1 h before supplementation of 100 μM inosine and neurons were harvested at 10 min after the supplementation (n = 5) (j). Cell extract was analyzed by Western blotting and quantitation of the density of bands representing phosphorylated MAPK (pMAPK) was assessed by densitometric scanning and expressed relative to the band at 0 μM of inosine. *P < 0.05, versus 0 μM of inosine. Data represent mean ± s.e.
