TY - JOUR
T1 - Changes in nNOS and NADPH diaphorase in frog retina and tectum after axotomy and FGF-2 application
AU - Soto, Ileana
AU - López-Roca, Teresa
AU - Blagburn, Jonathan M.
AU - Blanco, Rosa E.
N1 - Funding Information:
The authors would like to thank Clarissa del Cueto for expert technical assistance. REB is supported by NIH-SCORE SO6 GM008224 and RCMI G12 RR03051, JMB by NIH R01 NS45547, NIH-SCORE SO6 GM008224, and RCMI G12 RR03051. The confocal microscope was purchased with NSF MRI DBI 0115825.
PY - 2006/8/4
Y1 - 2006/8/4
N2 - We have shown previously that application of fibroblast growth factor-2 (FGF-2) to the cut optic nerve of the frog, Rana pipiens, augments the survival of retinal ganglion cells (RGCs). In this study, we examine the effects of axotomy and FGF-2 treatment upon the distribution of nitric oxide synthase (NOS) and NADPH diaphorase (NADPH-d) activity in the frog retina and tectum. We find that NOS and NADPH-d are largely absent from RGCs but present in amacrine neurons and in retinorecipient tectal layers. Axotomy alone has little effect on NOS expression or diaphorase activity, apart from slightly increasing the levels of expression in a subpopulation of amacrine cells that arborize in the On sublamina of the inner plexiform layer. FGF-2 application to the optic nerve down-regulates NOS expression and activity in the retina and up-regulates it in the tectum, particularly in retinorecipient layers. Electron microscopy of the optic nerve and neurofilament immunostaining of the tectum suggests that FGF-2 treatment increases the number of regenerating retinal axons arriving at the tectum. The effects in the retina and tectum are probably indirect, that in the retina being due to retrograde signaling from RGCs to amacrine neurons, and that in the tectum being due to re-induction of NOS expression in tectal neurons by the arrival of regenerating axons. At this stage, it appears unlikely that these changes in NOS play a role in the FGF-2′s survival effect on RGCs.
AB - We have shown previously that application of fibroblast growth factor-2 (FGF-2) to the cut optic nerve of the frog, Rana pipiens, augments the survival of retinal ganglion cells (RGCs). In this study, we examine the effects of axotomy and FGF-2 treatment upon the distribution of nitric oxide synthase (NOS) and NADPH diaphorase (NADPH-d) activity in the frog retina and tectum. We find that NOS and NADPH-d are largely absent from RGCs but present in amacrine neurons and in retinorecipient tectal layers. Axotomy alone has little effect on NOS expression or diaphorase activity, apart from slightly increasing the levels of expression in a subpopulation of amacrine cells that arborize in the On sublamina of the inner plexiform layer. FGF-2 application to the optic nerve down-regulates NOS expression and activity in the retina and up-regulates it in the tectum, particularly in retinorecipient layers. Electron microscopy of the optic nerve and neurofilament immunostaining of the tectum suggests that FGF-2 treatment increases the number of regenerating retinal axons arriving at the tectum. The effects in the retina and tectum are probably indirect, that in the retina being due to retrograde signaling from RGCs to amacrine neurons, and that in the tectum being due to re-induction of NOS expression in tectal neurons by the arrival of regenerating axons. At this stage, it appears unlikely that these changes in NOS play a role in the FGF-2′s survival effect on RGCs.
UR - http://www.scopus.com/inward/record.url?scp=33746210043&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33746210043&partnerID=8YFLogxK
U2 - 10.1016/j.brainres.2006.05.062
DO - 10.1016/j.brainres.2006.05.062
M3 - Article
C2 - 16808907
AN - SCOPUS:33746210043
SN - 0006-8993
VL - 1103
SP - 65
EP - 75
JO - Brain Research
JF - Brain Research
IS - 1
ER -