Depression of nociceptive sympathetic reflexes by the intrathecal administration of midazolam.

Abstract

The effect of the intrathecal administration of midazolam 0.5-1.0 mg in 1-2 ml of physiological saline solution, has been observed on responses evoked in renal sympathetic nerves by supramaximal electrical stimulation of radial and tibial nerves. In artificially ventilated dogs anaesthetized with alpha-chloralose, the intrathecal administration of midazolam caused a marked depression of reflexes evoked from the tibial nerve but had no effect on either spontaneous sympathetic activity or reflexes evoked by radial nerve stimulation. Neither the small amount (1-2 microliters) of benzyl alcohol, present as a preservative (administered intrathecally), nor midazolam 1 mg kg-1 i.v. caused any significant depression of the evoked somato--sympathetic reflexes. The effects of intrathecal midazolam were reversed by the benzodiazepine antagonists Ro 15-1788 1 mg kg-1 i.v. and Ro 15-3505 1-2 mg kg-1 i.v. but not by naloxone 2 mg i.v. It is suggested that the antinociceptive effect of locally applied midazolam could be the result of a non-opioid GABA-mediated system which may have implications in the management of pain.

• Authors: D Niv, J G Whitwam, L Loh
• Journal: British journal of anaesthesia (Br J Anaesth) Vol. 55 Issue 6 Pg. 541-7 (Jun 1983) ISSN: 0007-0912 [Print] England
• PMID: 6134538 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Anxiety Agents
• Benzodiazepines
• Midazolam

Topics

• Animals
• Anti-Anxiety Agents (pharmacology)
• Benzodiazepines (antagonists & inhibitors, pharmacology)
• Depression, Chemical
• Dogs
• Electric Stimulation
• Evoked Potentials (drug effects)
• Injections, Spinal
• Kidney (innervation)
• Midazolam
• Nociceptors (physiology)
• Radial Nerve (physiology)
• Reflex (drug effects)
• Sympathetic Nervous System (physiology)
• Tibial Nerve (physiology)
• Time Factors