DA-6034 Induces Ca2+i Increase in Epithelial Cells

DA-6034, a eupatilin derivative of flavonoid, has shown potent effects on the protection of gastric mucosa and induced the increases in fluid and glycoprotein secretion in human and rat corneal and conjunctival cells, suggesting that it might be considered as a drug for the treatment of dry eye. However, whether DA-6034 induces Ca2+ signaling and its underlying mechanism in epithelial cells are not known. In the present study, we investigated the mechanism for actions of DA-6034 in Ca2+ signaling pathways of the epithelial cells (conjunctival and corneal cells) from human donor eyes and mouse salivary gland epithelial cells. DA-6034 activated Ca2+-activated Cl- channels (CaCCs) and increased intracellular calcium concentrations ([Ca2+]i) in primary cultured human conjunctival cells. DA-6034 also increased [Ca2+]i in mouse salivary gland cells and human corneal epithelial cells. [Ca2+]i increase of DA-6034 was dependent on the Ca2+ entry from extracellular and Ca2+ release from internal Ca2+ stores. Interestingly, these effects of DA-6034 were related to ryanodine receptors (RyRs) but not phospholipase C/inositol 1,4,5-triphosphate (IP3) pathway and lysosomal Ca2+ stores. These results suggest that DA-6034 induces Ca2+ signaling via extracellular Ca2+ entry and RyRs-sensitive Ca2+ release from internal Ca2+ stores in epithelial cells.

Erectile potentials of a new phosphodiesterase type 5 inhibitor, DA-8159, in diet-induced obese rats / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To examine the changes in the erectile function in diet-induced obese rats and investigate the oral efficacy of DA-8159, a new phosphodiesterase type 5 (PDE5) inhibitor, on penile erection in obese rats.</p><p><b>METHODS</b>The rats were fed a high-energy diet for 12 weeks and divided into three groups: an obesity-resistant (OR) control group, an obesity-prone (OP) control group, and an OP-DA-8159 treatment (DA-8159) group. The electrostimulation-induced erectile responses were measured in all groups. The body weight, plasma cholesterol, triglyceride and glucose levels were also measured.</p><p><b>RESULTS</b>In the OP control group, the maximum intracavernous pressure (ICP) and ICP/blood pressure (ICP/BP) ratio after electric stimulation were significantly lower than those in OR control group. The corresponding area under the curve (AUC) of the ICP/BP ratio, the detumescence time and the baseline cavernous pressure were also lower than those in the OR control group, but this difference was not significant. The body weight gain, plasma cholesterol and triglyceride level in the OP group were significantly higher than those in the OR group. After administering the DA-8159, a significant increase in the maximum ICP and the ICP/BP ratio were observed. The corresponding AUCs in the DA-8159 group were also higher than those in the two control groups. Furthermore, the detumescence time was significantly prolonged after treatment with DA-8159.</p><p><b>CONCLUSION</b>These results demonstrate that diet-induced obesity affects the erectile function in rats and these erectile dysfunction (ED) can be improved by the treatment with DA-8159, indicating DA-8159 might be a treatment option for ED associated with obesity.</p>

Effect of DA-8159, a Selective Phosphodiesterase Type 5 Inhibitor, on Electroretinogram and Retinal Histology in Rabbits

DA-8159, a selective inhibitor of phosphodiesterase type 5, was developed as a new drug for erectile dysfunction. The effect of DA-8159 on the electroretinogram (ERG) and the retinal histopathology were evaluated in rabbits. The ERG was performed prior to, and 1 and 5 hr after DA-8159 (5 to 30 mg/kg) administration. The plasma concentration of DA-8159 was determined at each time point, and retinal microscopic examination was also performed. There was no statistically significant ERG change at any dose or at any time. Though the 30 Hz flicker showed a prolongation of the implicit time at 5 hr after the administration of either DA-8159 15 mg or 30 mg/kg (p<0.05), but concurrent amplitude decreases were not statistically significant. At a dose of 5 mg/kg, no test drug was detected in the blood after either 1 or 5 hr. At either 15 mg/kg or 30 mg/kg, there was a dose-dependent increase in the blood concentration after 1 hr of drug administration, which decreased with time. In light and electron microscopic examinations of the retina, there was no remarkable change at any dose. These results suggest DA-8159 has a low risk potential to the retina, but further evaluation on the visual functions in human is needed.