Function and structure in retinal transplants.
Embryonic mammalian donor retina transplanted into the subretinal space of a mature host develops into a graft with well-organized, but atypical retinal structure. We tested the effect of this organization on rabbit-to-rabbit graft functional properties, isolating the graft to avoid contamination of graft responses by host retinal activity. Transient ON or ON-OFF spike-like responses and local electroretinograms (L-ERGs) were recorded simultaneously via a single electrode on the graft surface. These response components depended on stimulus diameter, sometimes in a way indicating antagonistic center-surround receptive field organization and spatial tuning (43%). Other times, the responses were an increasing function of stimulus diameter which saturated for large spots (57%). Response amplitudes were a monotonically-increasing function of light intensity over the narrow range tested. The L-ERGs were reminiscent of the proximal negative response or M-wave seen in normal retinas, which reflect light-induced amacrine cell activity. Thus, for the first time, we have shown that these subretinal grafts possess light-transduction and complex functional properties like those in normal retinas. They also possess the cellular complement and synaptic microcircuitry needed to form these physiological properties, Therefore, these results demonstrate a functional ability and capacity in transplants that is required if nerve cell transplantation surgery is to be done with therapeutic aims.
Adolph
A R
AR
Schepens Eye Research Institute, Boston, MA 02114, USA.
Zucker
C L
CL
Ehinger
B
B
Bergström
A
A
D000200:Action Potentials; D000818:Animals; D004558:Electric Stimulation; D004596:Electroretinography; D016332:Fetal Tissue Transplantation / Q000502:physiology; D010786:Photoreceptor Cells / Q000166:cytology / Q000502:physiology / Q000637:transplantation; D011817:Rabbits; D012160:Retina / Q000033:anatomy & histology / Q000502:physiology* / Q000637:transplantation*; D014184:Transplantation, Homologous