Neurokinin B receptor (NK3)-positive neurons expressing c-fos after chemical noxious stimulation on the peritoneum: a double staining study in the nucleus tractus solitarius of the rat.

Neurokinin B receptor (NKR; NK3)-like immunoreactivity (LI) was densely distributed in the nucleus tractus solitarius (NST) of the rat. Approximately 32% of the neurons with NKR-LI in the NST expressed c-fos protein after chemical irritation on the peritoneum with acetic acid. The present results suggest that neurons containing NKR in the NST may be involved in the integration of noxious afferent information from the peritoneum in the rat.