Abstract
Abstract: :
Purpose: The loss of photoreceptor cells induces the reorganization of horizontal cell processes in the retinas of FVB/N mice as they mature. The reorganization of horizontal cell processes might be attributed to excessive glutamate released from damaged photoreceptor cells. This study was conducted to clarify whether excessive glutamate induces the sprouting of horizontal cell processes. Methods: L-glutamate (5 mg/g) was injected subcutaneously into the FVB/N mouse at P5. Immunocytochemistry and western-blotting were performed using anti-calbindin, -neurofilament (NF)-M160 and NF-Hp200 antisera at certain developing stages. Results: The number of horizontal cells showed no significant differences between FVB/N mouse and L-glutamate injected mouse. The NF-M160 and NF-Hp200 immunoreactive area was also calculated in the OPL, but there was no difference between FVB/N mouse and L-glutamate treated mouse. Quantitative evaluation by immunoblotting confirmed that the level of calbindin expression significantly increased in the L-glutamate-treated mouse than in the non-treated mouse. From P14 onwards, more numerous processes emerged from horizontal cells, descended into the inner plexiform layer (IPL), and formed a loose network in stratum 1 of the IPL. Conclusion: Our results suggest that excessive glutamate released from damaged photoreceptor cells might induce the reorganization of horizontal cell processes in the retinas of FVB/N mice as they mature.
Keywords: 561 retinal degenerations: cell biology • 426 horizontal cells • 520 plasticity