Extracellular nucleotides are important neurotransmitters, neuromodulators and paracrine factors in the neural sensory system [16]. Most of purines and pyrimidines act on the associated purinergic cell-surface receptors to mediate sensory transduction and modulation. Previously, we reported a subgroup of heptaldehyde (H)/2-hepatanone (Ho)-responsive olfactory sensory neurons (H/Ho-OSNs) in the ventral endoturbinates [31]. Through the calcium image recording, we characterized that ATP elicited [Ca2+](i) increase in the presence of extracellular calcium, while depletion of intracellular calcium stores blocked UTP-evoked [Ca2+](i) increase. Pharmacological studies indicated that P2X(3) was expressed in the H/HoOSNs, modulating both heptaldehyde (H) and 2-hepatanone (Ho)-induced responses. These data indicated that activation of purinergic receptor negatively modulated odor response, providing the evidence to support the possible protective effect of purinergic receptor in OSNs. (C) 2015 Elsevier Inc. All rights reserved.