Abstract： Accumulating evidence demonstrates that the nucleus tractus solitarii (NTS) neurons serve as central respiratory chemoreceptors,but the underlying molecular mechanisms remain undefined.The present study investigated the expression of acid-sensitive ether-à-go-go-gene-like (Elk,Kv12) channels in the NTS of mice.Immunofluorescence staining was used to observe the distribution and cellular localization of the Kv12 channels in NTS neurons.Western blot and quantitative real-time PCR (qPCR) were used to evaluate protein and mRNA expression levels of Kv12 channels.The results showed that all of the three members (Kv12.1,Kv12.2,Kv12.3) of the Kv12 channel family were expressed in NTS neurons,and their expressions were co-localized with paired-like homeobox 2b gene (Phox2b) expression.The expression of Kv12.1 mRNA was the largest,whereas the expression of Kv12.3 was the least in the NTS.The results suggest Kv12 channels are expressed in Phox2b-expressing neurons in the NTS of mice,which provides molecular evidence for pH sensitivity in Phox2b-expressing NTS neurons.