Sci. STKE, 1 August 2000
Channels One Channel at a Time
Many neurons express multiple types of receptors and receive multiple signals. The cellular response results from integration of these signals. Khakh et al. found that activation of the purinergic receptor, P2X, was able to inhibit the opening of nicotinic acetylcholine receptors (nAChRs). When activated by simultaneous application of ATP and acetylcholine (ACh), α3β4 nAChR and P2X receptors expressed in Xenopus oocytes demonstrated nonadditive currents that were the same amplitude as currents evoked by ATP alone. Experiments with an open channel blocker for the nAChR indicated that simultaneous activation of the P2X receptor blocked opening of the nAChR. The ability of the P2X receptor to inhibit the nAChR was dependent on the density of the channels, suggesting that the two channels physically interact. The authors showed that, in myenteric neurons, application of ATP inhibits evoked cholinergic currents, indicating that the cross-inhibition is physiologically relevant.
Khakh, B.S., Zhou, X., Sydes, J., Galligan, J.J., and Lester, H.A. (2000) State-dependent cross-inhibition between transmitter-gated cation channels. Nature 406: 405-410. [Online Journal]
Citation: One Channel at a Time. Sci. STKE 2000, tw2 (2000).
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