Sympathoinhibitory Action of Nociceptin in the Rat Spinal Cord
Document Type
Conference Proceeding
Publication Date
3-27-2002
Description
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.
Citation Information
Brailoiu, G. C.; Lai, C. C.; Chen, C. T.; Hwang, L. L.; Lin, H. H.; and Dun, N. J.. 2002. Sympathoinhibitory Action of Nociceptin in the Rat Spinal Cord. Clinical and Experimental Pharmacology and Physiology. Vol.29(3). 233-237. https://doi.org/10.1046/j.1440-1681.2002.03635.x PMID: 11906490 ISSN: 0305-1870
