Sympathoinhibitory action of nociceptin in the rat spinal cord

G. C. Brailoiu, C. C. Lai, C. T. Chen, L. L. Hwang, H. H. Lin, N. J. Dun

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


1. Whole-cell patch recordings were made from antidromically identified sympathetic preganglionic neurons (SPN) of immature rat spinal cord slices. Bath application of nociceptin (0.1-1 μmol/L) suppressed excitatory postsynaptic potentials (EPSP) and hyperpolarized a population of SPN; these effects were naloxone (1 μmol/L) insensitive. 2. Nociceptin suppressed the amplitude of EPSP without causing a concomitant change in glutamate-induced depolarizations, suggesting a presynaptic inhibitory action. 3. Analysis of current-voltage relationships showed that nociceptin hyperpolarized SPN by increasing an inwardly rectifying K+ current. 4. Intrathecal injection of nociceptin (3, 10 and 30 nmol) to urethane-anaesthetized rats dose-dependently reduced the mean arterial pressure and heart rate; these effects were not prevented by prior intravenous injection of naloxone (1 mg/kg). 5. Results from our in vitro and in vivo experiments suggest that nociceptin suppresses spinal sympathetic outflow either by attenuating excitatory synaptic responses or hyperpolarizing SPN.

Original languageEnglish
Pages (from-to)233-237
Number of pages5
JournalClinical and Experimental Pharmacology and Physiology
Issue number3
Publication statusPublished - 2002


  • Intermediolateral cell column
  • Naloxone
  • Nociceptin
  • Opioids
  • Orphanin FQ
  • Spinal cord
  • Sympathetic preganglionic neurons

ASJC Scopus subject areas

  • Physiology
  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)


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