If you want to blend in with the locals, it helps to speak their language. So when Stanford University scientists wanted to converse with retinal and other nerve cells, they looked to the language of neurotransmitters. Nerve cells release these chemicals into a specialized adjacent gap called a synapse, enabling them to communicate with neighboring cells. Creating a device that speaks the neurons' lingo will contribute to a new generation of implantable substitutes for some retinas compromised by macular degeneration. Such "artificial synapse chips" might replace other kinds of diseased neurons, too.

Neurons normally convert chemical messages into electrical impulses, so the conventional strategy in creating artificial retinas involves electrically stimulating remaining healthy nerve cells. But the Stanford group says that chemical stimulation has various advantages over electrical stimulation. One major plus stems from the fact that neurons use different neurotransmitters to fine-tune the responses they evoke. Moreover, the same neurotransmitter can induce different responses depending on the target cell's characteristics. "Not all pathways are equal," states team leader Harvey Fishman, who directs the Stanford Ophthalmic Tissue Engineering Laboratory. Electrical stimulation could indiscriminately activate functions in the neighboring cell.

This article was originally published with the title Chemical Conversations.

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