Choline acetyltransferase‐immunoreactive neurons in the retina of normal and dark‐reared turtle

Abstract

Visual deprivation alters retinal-ganglion-cell response properties through changes in spontaneous wave-like activity (Sernagor and Grzywacz [1996] Curr Biol 6:1503-1508). This activity depends on cholinergic synaptic transmission in the turtle retina (ibid; Sernagor and Mehta [ 2001] J Anat 199:375-383). We studied the expression of choline acetyltransferase (ChAT) by immunocytochemistry and Western blot in developing retinas of control and dark-reared turtles. At postnatal day 0 (P0), right after hatching, ChAT-immunoreactivity was present in the ganglion cell layer (GCL), in the inner nuclear layer (INL), and in two distinct bands of the inner plexiform layer (IPL). In P14- and P28-control, and P14- and P28-dark-reared retinas, ChAT-immunoreactivity showed similar patterns to those in P0. However, in P14- and P28-dark-reared retinas the density of ChAT-immunoreactive cells was higher in both the INL and GCL than in P14- and P28-control retinas, respectively. Moreover, Western blotting showed that ChAT protein levels were significantly increased in the dark-reared retina compared to those of the control. TUNEL studies indicated that the difference between normal and dark-reared conditions was not due to extra apoptosis in the former. In turn, proliferating-cell nuclear antigen immunocytochemistry showed no extra proliferating cells in the latter. Finally, nearest-neighbor analysis revealed that the denser population of cholinergic cells in dark-reared turtles formed a mosaic as regular as the normal ones in the GCL. Thus, light deprivation increases the expression of ChAT, increasing the apparent density of cholinergic neurons in the developing turtle retina.

Efferent innervation of turtle semicircular canal cristae: Comparisons with bird and mouse

“…We also included mouse brain as an additional control. The ChAT antibody used in this study has been shown previously to detect a single 68-70 kd band in turtle retina (Lee et al, 2007). In agreement with that study, we detected a prominent band of the appropriate size (73 kDa) in both turtle brain and ear (Fig.…”

“…Within the auditory and vestibular system, AB144P has been characterized in the inner ear of lizard (Wibowo et al, 2009), mouse (Kong et al, 2002), rat (Kong et al, 1994b), and human (Kong et al, 1994a(Kong et al, , 1998. This ChAT antibody has been shown by western blot to detect a single 68-70 kd band in turtle retina, as well as the brains of fish, lizards, and rat (Anad on et al, 2000;Lee et al, 2007;Wibowo et al, 2009). In our hands, we detected a doublet of bands via western blotting at 70 kd in turtle or a single band with mouse brain tissue extracts running at a slightly higher MW (Fig.…”

Spontaneous Activity Promotes Synapse Formation in a Cell-Type-Dependent Manner in the Developing Retina

“…Their arrangement into mosaics is thought to help neuronal cell types cover the retinal surface evenly and represent visual space homogeneously (Masland, 2001; Wassle, 2004). To what extent activity regulates the formation and maintenance of mosaics is incompletely understood (Zhang et al, 2005; Lee et al, 2007; Anishchenko et al, 2010). We analyzed the lateral distribution of two representative cell types in the inner retina.…”

Early afferent signaling in the outer plexiform layer regulates development of horizontal cell morphology

“…1c). Finally, we examined the cholinergic amacrine cells, a cell type that has been reported to increase (Lee et al,2007) or decrease (Zhang et al,2005) in number in response to dark‐rearing. Neither the cholinergic amacrine cells in the ganglion cell layer (GCL), nor those in the inner nuclear layer (INL), differed significantly in their numbers between the control and dark‐reared animals (Fig.…”