Enkephalinergic neurons express 5-HT3 receptors in the spinal cord dorsal horn: single cell RT-PCR analysis.
The analgesic effect of activation of 5-HT3 receptors at the spinal cord is attenuated by the opioid antagonist naloxone. Enkephalin-immunoreactive neurons in the spinal cord superficial dorsal horn are innervated by 5-HT-immunoreactive fibers. This prompted us to examine whether enkephalinergic dorsal horn neurons express 5-HT3 receptors. Using the technique of single-cell RT-PCR adapted for small neurons in the superficial dorsal horn, methionine-enkephalin sequence-specific PCR products were observed in about half of the neurons studied. Furthermore, 5-HT3 receptor mRNA was detected in approximately 25% of enkephalinergic neurons. These observations suggest that at least part of the antinociception elicited by activation of 5-HT3 receptors at the spinal cord may involve enkephalinergic dorsal horn neurons.
Tsuchiya
M
M
Department of Physiology, Dokkyo University School of Medicine, Mibu, Tochigi, Japan.
Yamazaki
H
H
Hori
Y
Y
D000818:Animals; D004744:Enkephalin, Methionine / Q000235:genetics / Q000378:metabolism*; D066298:In Vitro Techniques; D009474:Neurons / Q000378:metabolism* / Q000502:physiology; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism* / Q000502:physiology
D012333:RNA, Messenger; D011985:Receptors, Serotonin; D004744:Enkephalin, Methionine