Intrathecal administration of a new nitric oxide donor, NOC-18, produces acute thermal hyperalgesia in the rat.

Abstract

A nitric oxide releasing compound, NOC-18, was injected intrathecally in order to determine the role of NO in spinal nociceptive mechanisms in rats. The nociceptive threshold was evaluated by the radiant heat tail-flick test. The effects of intrathecal injection of N-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor; methylene blue (MB), a soluble guanylate cyclase inhibitor and hemoglobin (Hb), an NO scavenger, on the nociceptive threshold were measured in the presence and absence of 0.1, 1 and 10 microg of NOC-18. The results were compared with a control group of rats which were injected with the same volume of normal saline. NOC-18 caused a dose-dependent curtailment of the tail-flick latency during the period from 15 to 150 min. L-NAME, MB and Hb all produced prolongation of the tail-flick latency during the same time period. The hyperalgesia induced by this concentration range of NOC-18 was completely blocked by Hb, but was not affected by either L-NAME or MB. These findings indicate that NO plays a direct role in thermal hyperalgesia in the spinal cord, and that an another pathway in addition to the NO-cGMP pathway may be involved.

• Authors: T Inoue, T Mashimo, S Shibuta, I Yoshiya
• Journal: Journal of the neurological sciences (J Neurol Sci) Vol. 153 Issue 1 Pg. 1-7 (Dec 09 1997) ISSN: 0022-510X [Print] Netherlands
• PMID: 9455970 (Publication Type: Journal Article)

Chemical References

• Enzyme Inhibitors
• Hemoglobins
• NOC 18
• Nitroso Compounds
• Nitric Oxide
• Nitric Oxide Synthase
• Guanylate Cyclase
• NG-Nitroarginine Methyl Ester

Topics

• Animals
• Enzyme Inhibitors (pharmacology)
• Guanylate Cyclase (antagonists & inhibitors)
• Hemoglobins (pharmacology)
• Hot Temperature
• Hyperalgesia (chemically induced, psychology)
• Injections, Spinal
• Male
• NG-Nitroarginine Methyl Ester (pharmacology)
• Nitric Oxide (metabolism)
• Nitric Oxide Synthase (antagonists & inhibitors)
• Nitroso Compounds (administration & dosage, pharmacology)
• Pain Measurement (drug effects)
• Rats
• Rats, Sprague-Dawley
• Reaction Time (drug effects)