Na+ action potentials in human photoreceptors

Fusao Kawai, Masayuki Horiguchi, Hiromitsu Suzuki, Ei Ichi Miyachi

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)


Mammalian photoreceptors are hyperpolarized by a light stimulus and are commonly thought to be nonspiking neurons. We used the whole-cell patch-clamp technique on surgically excised human retina to examine whether human photoreceptors can elicit action potentials. We discovered that human rod photoreceptors express voltage-gated Na+ channels, and generate Na+ action potentials, in response to membrane depolarization from membrane potentials of -60 or -70 mV. Na+ spikes in human rods were elicited at the termination of a light response that hyperpolarized the potential well below -50 mV. This served to amplify the release of a neurotransmitter when a bright light is turned off, and thus selectively amplify the off response to the light signal.

Original languageEnglish
Pages (from-to)451-458
Number of pages8
Issue number2
Publication statusPublished - 2001

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)


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