Dentification and Characterization of a Subset of Ouse Sensory Neurons That Express Acid-sensing on Channel

bstract—Acid-sensing ion channel 3 (ASIC3) is the m ensitive acid sensor in sensory neurons that innervate kin, muscle, heart, and visceral tissues. ASIC3 is involve schemia sensing, nociception, mechanosensation, and he ng, but how ASIC3-expressing neurons differ in their fi roperties is still unknown. We hypothesized that AS xpressing neurons have specialized firing propertie hich, coupled with the heterogeneity of acid-sensing pr rties, accounts for various physiological roles. Here, uccessfully identified ASIC3-expressing lumbar dorsal ro anglion (DRG) neurons whose transient proton-gated c ents were blocked by salicylic acid (SA). The salicylic ensitive (SAS) neurons did not exist in DRG neurons of acking ASIC3. SAS neurons expressed distinct electroph ological properties as compared with other DRG neuro specially, SAS neurons fired action potentials (APs) w arge overshoot and long afterhyperpolarization duratio hich suggests that they belong to nociceptors. SAS ons also exhibited multiple nociceptor markers such as aicin response (38%), action potential (AP) with inflec 35%), or tetrodotoxin resistance (31%). Only in SAS neu ut not other DRG neurons was afterhyperpolarization d ion correlated with resting membrane potential and AP ation. Our studies reveal a unique feature of ASIC3-expr ng DRG neurons and a basis for their heterogene unctions. © 2008 IBRO. Published by Elsevier Ltd. All r eserved.