Editors' ChoicePERCEPTION

Channeling Specific Sensations

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Science's STKE  08 Jul 2003:
Vol. 2003, Issue 190, pp. tw259-TW259
DOI: 10.1126/stke.2003.190.tw259

Shin et al. determined that Cav3.2 channels, a type of T-type calcium channels, were specifically expressed in D-hair receptors, a distinct class of sensory neuron. Sensory neurons with their cell bodies in the dorsal root ganglia (DRG) mediate the sensations of cutaneous touch and pain. Different tactile sensations are recognized by specific types of sensory neurons with distinct physiological responses; the molecular distinctions among different classes of sensory neurons, however, remain unclear. Shin et al. used a combination of DNA microarray analysis, suppressive subtractive hybridization, and quantitative real-time polymerase chain reaction to identify genes whose expression was specifically reduced in neurotrophin 4 (NT-4) knockout mice (NT-4−/−), which lose D-hair receptor neurons during development but have no other sensory deficits. The authors used in situ hybridization on the candidate genes thus identified to search for genes whose expression was restricted to a particular sensory neuronal subtype and was lost in the mutant mice with an appropriate time course. Two genes were identified by these criteria: The gene encoding the receptor for NT-4 and the gene encoding the Cav3.2 calcium channel. Electrophysiological and pharmacologic analysis indicated that the Cav3.2 calcium channel was required for D-hair receptor function. Identification of a particular class of channel as essential to the function of particular class of sensory neurons provides a key step toward determining the molecular mechanisms underlying the individual properties of the different types of neurons mediating different modalities of somatosensory response.

J. B. Shin, C. Martinez-Salgado, P. A. Heppenstall, G. R. Lewin, A T-type calcium channel required for normal function of a mammalian mechanoreceptor. Nat. Neurosci. 6, 724-730 (2003). [Online Journal]

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