The vertebrate retina has a unique position within the panoply of the nervous system networks: our understanding of its complex circuitry of... » More

The vertebrate retina has a unique position within the panoply of the nervous system

networks: our understanding of its complex circuitry of interacting neurons and glia has become

the gold standard of our current knowledge of network operations. This presentation is about

work from my laboratory that contributed to some of the concepts that support our

contemporary views of the functional retina. Early in the pursuit of retinal function, a vital issue

was that of understanding the synaptic mechanisms and neurotransmitters required for

information to flow from the photoreceptors to the ganglion cells. My research contributions to

this effort included the discovery of inhibition and the GABA and glycine modes of inhibitory

mechanisms. Our work on inhibition was followed by the discovery of the APB (mGluR6)

receptor of On bipolars, the first metabotropic glutamate receptor described in the nervous

system. This was followed by a body of work carried out in salamander and rabbit retinas on the

pathways of glutamatergic excitation revealed through the use of agonists and antagonists of

increasing selectivity. We separated sign conserving from sign inverting responses in the outer

retina and provided compelling evidence that bipolars, like photoreceptors, had a glutamatergic

mode of neurotransmission. We identified NMDA (N-methyl-D-aspartate)and KA (Kainic

Acid)/AMPA (?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors in amacrine

and ganglion cells and revealed that both receptor classes were activated by light. Additional

studies on neuropeptides illustrated how many of these, including Substance P, somatostatin and

neurotensin had actions such that they should be considered as major neuromodulators in the

retina. My laboratory also made significant contributions to structure/function relationships and

mechanisms of glial-neuronal interactions.

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