Bi-directional effects of intrathecal NMDA and substance P on rat dorsal horn neuronal responses.
Intrathecal NMDA (5 ng) facilitated wind-up but not C-fibre evoked responses, whereas 50 ng facilitated C-fibre and A delta-fibre evoked responses but not wind-up of convergent dorsal horn neurones in the halothane anaesthetized rat. Higher doses of NMDA and SP (10-500 ng) were without effect. Co-administered SP (10 ng) with NMDA (5 ng) facilitated A delta-fibre evoked responses and wind-up. Excitatory amino acid and peptide interactions are discussed.
Chapman
V
V
Department of Pharmacology, University College London, UK.
Dickenson
A H
AH
Tjølsen
A
A
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005071:Evoked Potentials / Q000187:drug effects; D007278:Injections, Spinal; D016202:N-Methylaspartate / Q000008:administration & dosage / Q000494:pharmacology*; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000502:physiology; D013373:Substance P / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
D013373:Substance P; D016202:N-Methylaspartate