A molecular approach to retinal neural networks.
Our understanding of the computations carried out by neural networks in the central nervous system is limited by our incomplete knowledge of the diversity of cell types and the multiplicity of their functions. In the retina, over fifty cell types encode the spatial, temporal, and chromatic parameters of the incoming light stimuli to generate the messages of action potentials that travel to the brain along the fibers of the optic nerve. We have combined molecular techniques with microscopy and electrophysiology to study a rare cell type in the retina, the dopaminergic amacrine (interplexiform cells). These neurons were labeled in transgenic mice with human placental alkaline phosphatase so that they could be identified in vitro for patch-clamping and analysis of gene expression by single-cell RT-PCR and cDNA array profiling. We have thus demonstrated that the retinal dopaminergic neurons spontaneously generate action potentials in a rhythmic fashion, release dopamine over their entire surface, establish GABAergic synapses and contain proteins whose existence went undetected with more conventional techniques.
Raviola
Elio
E
Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA. elio_raviola@hms.harvard.edu
D025042:Amacrine Cells / Q000000981:diagnostic imaging / Q000502:physiology*; D000818:Animals; D016172:DNA Fingerprinting; D004298:Dopamine / Q000502:physiology*; D006801:Humans; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D008854:Microscopy, Electron; D016571:Neural Networks, Computer; D018408:Patch-Clamp Techniques; D012160:Retina / Q000033:anatomy & histology / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014463:Ultrasonography
D004298:Dopamine