Preprodynorphin-like immunoreactivity in medullary dorsal horn neurons projecting to the thalamic regions in the rat.
Preprodynorphin (PPD)-like immunoreactive (-LI) neuronal cell bodies in the trigeminal sensory nuclear complex of the rat were found in laminae I and II of the medullary dorsal horn (MDH; caudal spinal trigeminal nucleus) and the paratrigeminal nucleus. A PPD immunofluorescence histochemistry combined with a fluorescence retrograde tract-tracing method revealed that some of the PPD-LI neurons in the MDH and paratrigeminal nucleus projected to the thalamic regions. Nociceptive nature of the PPD-LI MDH neurons projecting to the thalamic regions was also demonstrated by a triple labeling method, using the technique of the noxious stimulus-evoked expression of the immediate-early gene, c-fos. In the rats which were subcutaneously injected with formalin into the upper and lower lips, c-fos protein (Fos) was found in PPD-LI neurons which were labeled with a retrograde tracer injected into the thalamic regions.
D000818:Animals; D004399:Dynorphins / Q000378:metabolism*; D005557:Formaldehyde / Q000494:pharmacology; D007279:Injections, Subcutaneous; D008046:Lip / Q000187:drug effects / Q000502:physiology; D008297:Male; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D009619:Nociceptors / Q000502:physiology; D010146:Pain / Q000503:physiopathology; D011498:Protein Precursors / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*; D013788:Thalamus / Q000502:physiology*; D014278:Trigeminal Nuclei / Q000166:cytology / Q000378:metabolism; D014279:Trigeminal Nucleus, Spinal / Q000166:cytology / Q000378:metabolism