The purpose of this study was to determine whether iganidipine, nimodipine and lomerizine, potentially useful calcium channel blockers for ophthalmic treatment, have direct retinal neuroprotective effects against hypoxic damage in experimental in vitro model. We used purified retinal ganglion cells (RGCs) from newborn rats. RGCs were incubated in controlled-atmosphere incubator in which oxygen levels were reduced to 5% normal partial pressure and cell viability was assessed. We also examined the effect of calcium channel blockers on the calcium ion concentration in RGC under hypoxic stress by calcium imaging. Iganidipine, nimodipine and lomerizine (0.01-1 microM) increased the RGC viability. Increase in intra-RGC calcium ion concentration by hypoxic damage was reduced by these calcium channel blockers. In conclusion, iganidipine, nimodipine and lomerizine were effective against hypoxic RGC damage in vitro. This neuroprotective effect was thought to be mediated by blocking calcium ion influx into RGC. These findings suggest that iganidipine, nimodipine and lomerizine have a direct neuroprotective effect against RGC damage related to hypoxia.

2005-01-01·Current Eye Research4区 · 医学

Ocular Distribution After Topical Instillation and Potential Neuroprotective Effect After Intravitreal Injection of the Calcium Channel Blocker Iganipidine

4区 · 医学

Article

作者: Shinichiro Saito ; Makoto Araie ; Yasuyuki Suzuki ; Yasuhiro Fukaya ; Kenji Kashwagi ; Masaaki Ohashi ; Atsuo Tomidokoro

PURPOSETo investigate the effects of iganidipine, a new calcium antagonist on glutamate agonist-induced retinal damage.METHODSIganidipine was injected with N-methyl-D-aspartate (NMDA) or kainic acid (KA) into the rat vitreous, and the retina was histologically examined. After co-injection with KA, the number of DiI-labeled retinal ganglion cells was also counted. Rabbits received unilateral instillation of 0.03% iganidipine twice daily for 14 days, and the iganidipine level in the posterior retina-choroid was determined by liquid chromatography/mass spectrometry.RESULTSCoadministration of iganidipine had no significant effect on NMDA-induced thinning of the inner plexiform layer but partly suppressed KA-induced thinning at final intravitreous concentrations of 10(-8) M or higher, which was confirmed by counting the ganglion cell number. The iganidipine level in the posterior retina-choroid was approximately 6.2 x 10(-7) M in the instilled eye, which was higher than on the contralateral side by 5.2 x 10(-7) M (p = 0.035).CONCLUSIONSIganidipine suppressed KA-induced retinal damage in rats. This suppression was achieved with a lower concentration than that resulting from unilateral instillations of iganidipine in the ipsilateral posterior retina-choroid in rabbits.

2004-01-01·Current Eye Research4区 · 医学

Topical administration of iganidipine, a new water-soluble ca²⁺antagonist, increases ipsilateral optic nerve head circulation in rabbits and cynomolgus monkeys

4区 · 医学

Article

作者: Ishii, Kiyoshi ; Araie, Makoto ; Tomita, Goji ; Fukaya, Yasuhiro

PURPOSETo evaluate the effects of topically administered iganidipine hydrochloride, a novel water-soluble Ca2+- channel blocker, on optic nerve head (ONH) circulation in Dutch rabbits and cynomolgus monkeys.METHODSONH tissue blood velocity (NBONH) was determined using the laser speckle method. In rabbits, NBONH was measured for 90 minutes before and after a single iganidipine administration, or before and after twice-daily ad- ministrations for 21 days (0.03%). In monkeys, NBONH was measured before and after twice-daily administrations of iganidipine for 7 days (0.03 or 0.1%).RESULTSIganidipine (0.03% solution) significantly increased NBONH by 8 to 10% in treated eyes after a single administration (p < 0.05) or by 18 to 35% after 7-, 14-, or 21-day twice-daily administration in rabbits (p < 0.05). In monkeys, 0.03% and 0.1% iganidipine significantly increased NBONH in treated eyes by 20 and 41% after 7-day (p < 0.05) twice-daily administration, respectively.CONCLUSIONTopical iganidipine significantly increased ONH blood velocity in treated eyes.

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