PKCy-immunoreactive Neurons In The Medullary And Spinal Orsal Horns Projecting To The Nucleus Submedius Of The Thalamus, Periaqueductal Grayand Solitary Tract Nucleus In The Rat

Protein kinase C (PKC) belongs to the molecular that is involved in the transmembrane intracellular signal transduction. PKC y subunit (PKCy) is an important member of the PKC. Previous studies have demonstrated that in the spinal dorsal horn PKCy takes part in the nociceptive information transmission and PKCy-immunoreactive neurons are located in the medullary and spinal dorsal horns. Objective: To examine the projection of PKCy-immunoreactive neurons from the medullary and spinal dorsal horns to the nucleus submedius of the thalamus, midbrain periaqueductal gray and solitary tract nucleus in the rat. Methods: By using fluoro-gold (FG) retrograde tracing combined with immunofluorescence histochemical staining for PKCy. Results: ?PKCy-immunoreactive neurons were mainly observed in the inner part of lamina II and the border area between laminae II and HI of the medullary and spinal dorsal horns. In laminae I and HI, some PKCy-immunofluorescence heavily stained large neurons were observed. In the lateral spinal nucleus, a few lightly stained PKCy-immunopositive small neurons were found. 〢fter injecting FGinto the nucleus submedius of the thalamus, FG retrogradely labeled neurons were mainly found in laminae I, ID of the medullary dorsal horn and I, III, V of the spinal dorsal horn and lateral spinal nucleus. Some of these FG-labeled neurons in lamina I of the medullary and spinal dorsal horns showed PKCy-immunoreactivities. 瓵fter injecting FG into the periaqueductal gray, FG retrogradely labeled neurons were also mainly found in laminae I, II, III of the medullary and spinal dorsal horns and lateral spinal nucleus. Some of these FG-labeled neurons in laminae I, II, III of the medullary and spinal dorsal horns and lateral spinal nucleus exhibited PKCY-immunoreactivities. 瓵fter injecting FG into the solitary tract nucleus, FG retrogradely labeled neurons were also mainly found in laminae I , II, III of the medullary and spinal dorsal horns and lateral spinal nucleus. Some of these FG-labeled neurons in laminae I , II?HI of the medullary and spinal dorsal horns and lateral spinal nucleus exhibited PKCy-immunoreactivities. Conclusions: ?PKCY-immunore-active neurons in the medullary and spinal dorsal horns send projection fibers to the nucleus submedius of the thalamus, midbrain periaqueductal gray and solitary tract nucleus in the rat. ㏕hese PKCy-immunoreactive neurons might be involved in the transmission of visceral and nociceptive information from the medullary and spinal dorsal horns to the thalamus, periaqueductal gray and solitary tract nucleus.