Article

Retinal TrkB receptors regulate neural development in the inner, but not outer, retina.

Neuroscience Program, School of Medicine, University of California San Francisco, San Francisco, California 94143, USA.
Molecular and Cellular Neuroscience (impact factor: 3.66). 08/2008; 38(3):431-43. DOI:10.1016/j.mcn.2008.04.004 pp.431-43
Source: PubMed

ABSTRACT BDNF signaling through its TrkB receptor plays a pivotal role in activity-dependent refinement of synaptic connectivity of retinal ganglion cells. Additionally, studies using TrkB knockout mice have suggested that BDNF/TrkB signaling is essential for the development of photoreceptors and for synaptic communication between photoreceptors and second order retinal neurons. Thus the action of BDNF on refinement of synaptic connectivity of retinal ganglion cells could be a direct effect in the inner retina, or it could be secondary to its proposed role in rod maturation and in the formation of rod to bipolar cell synaptic transmission. To address this matter we have conditionally eliminated TrkB within the retina. We find that rod function and synaptic transmission to bipolar cells is not compromised in these conditional knockout mice. Consistent with previous work, we find that inner retina neural development is regulated by retinal BDNF/TrkB signaling. Specifically we show here also that the complexity of neuronal processes of dopaminergic cells is reduced in conditional TrkB knockout mice. We conclude that retinal BDNF/TrkB signaling has its primary role in the development of inner retinal neuronal circuits, and that this action is not a secondary effect due to the loss of visual signaling in the outer retina.

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Keywords

BDNF signaling
 
BDNF/TrkB signaling
 
bipolar cell synaptic transmission
 
conditional knockout mice
 
conditional TrkB knockout mice
 
inner retina neural development
 
inner retinal neuronal circuits
 
neuronal processes
 
photoreceptors
 
pivotal role
 
primary role
 
proposed role
 
retinal BDNF/TrkB signaling
 
retinal ganglion cells
 
rod maturation
 
second order retinal neurons
 
secondary effect
 
TrkB knockout mice
 
TrkB receptor
 
visual signaling