Localization of the neurokinin 1 receptor on a subset of substance P-positive and isolectin B4-negative dorsal root ganglion neurons of the rat.

Dorsal root ganglion (DRG) neurons that express the neurokinin 1 (NK1) receptor were further characterized immunocytochemically using double-labeling techniques. DRG neurons were isolated from adult rats and cultured for 1-4 days. NK1 receptors on the surface of the neurons were labeled with substance P-gold. Non-peptidergic neurons were labeled with the surface marker isolectin B4 from Griffonia simplicifolia (IB4). Substance P-immunoreactivity was determined using an antibody to substance P. NK1 receptors were not identified on non-peptidergic neurons. The vast majority of the neurons with NK1 receptors showed substance P-immunoreactivity suggesting that NK1 receptors are autoreceptors in many dorsal root ganglion neurons.