Preproenkephalin gene expression in the rat spinal cord after noxious stimuli.
The trans-synaptically activated biosynthesis of the preproenkephalin (PPE) mRNA in the dorsal horn of the rat lumbar spinal cord was examined by an in situ hybridization histochemical technique. As a nociceptive stimulus, a small amount of formalin was injected into the right hindpaw, and quantitative and qualitative changes of PPE-mRNA expression were determined by emulsion autoradiography. Formalin injection was found to result in a significant increase in the number and signal intensity of neurons expressing PPE-mRNAs in the superficial and deep layers of the ipsilateral spinal dorsal horn. Expression of PPE-mRNA increased within 1 h after formalin injection in neurons of deep layers, but gradually for at least 24 h in neurons in the superficial layers. These results at the level of the spinal cord showed that differential responses of PPE neurons related to the pain sensation occurred trans-synaptically after nociceptive stimulation applied to the periphery.
Noguchi
K
K
Department of Anatomy, Osaka University Medical School, Japan.
Morita
Y
Y
Kiyama
H
H
Sato
M
M
Ono
K
K
Tohyama
M
M
D000818:Animals; D004745:Enkephalins / Q000235:genetics* / Q000502:physiology; D005786:Gene Expression Regulation; D008297:Male; D009693:Nucleic Acid Hybridization; D010146:Pain / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000378:metabolism* / Q000503:physiopathology
D004745:Enkephalins; D011498:Protein Precursors; D012333:RNA, Messenger; C033660:preproenkephalin