Neuropeptide Y (NPY)-immunoreactive nerve fibers in the intermediolateral cell column of rat spinal cord segments T2-T3 and T8-T10 and rabbit segments T3-T6 were studied with light and electron microscopic immunocytochemistry. Plexuses of NPY-immunoreactive nerve fibers were found by light microscopy. NPY-positive synapses were present electron microscopically but non-immunoreactive synapses greatly outnumbered NPY-immunoreactive ones. In the lateral horn of rat T9, 30% of the vesicle-containing NPY-positive axon profiles formed synapses, 95% of which were axodendritic. These synaptic connections may mediate the effects of brainstem NPY neurons on the activity of sympathetic preganglionic neurons.
- Blood pressure
- Intermediolateral cell column
- Neuropeptide Y
- Spinal cord