Objective: Zonula occludens-1 (ZO-1) is cytoplasmic component of tight junction (TJ), serving as a basis for TJ assembly as well as a key regulator of TJ structure and function.We previously reported that activation of transient receptor potential vanilloid subtype 1 (TRPV1) in rabbit submandibular gland promoted salivary secretion partly via an increase in paracellular permeability.However, the involvement of ZO-1 in TRPV 1-modulated paracellular permeability was still undetermined.Here we explored the effect and mechanism of TRPV1 activation on ZO-1 in rat submandibular gland(SMG).