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Midazolam inhibits cardiac nociception evoked by coronary artery occlusion in rats

Published online by Cambridge University Press:  01 June 2008

Z. Guo*
Affiliation:
Shanxi Medical University and Second Hospital of Shanxi Medical University, Departments of Anesthesiology, Taiyuan, Shanxi, PR China
D.-J. Yuan
Affiliation:
Shanxi Medical University and Second Hospital of Shanxi Medical University, Departments of Anesthesiology, Taiyuan, Shanxi, PR China
*
Correspondence to: Zheng Guo, Departments of Anesthesiology, Shanxi Medical University and Second Hospital of Shanxi Medical University, 56 Xinjian Nan Road, Taiyuan 030001, Shanxi, PR China. E-mail: [email protected]; Tel: +86 351 4174387; Fax: +86 351 2024239
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Summary

Background and objectives

This study was designed to investigate the potential existence of the response of neurons in the parafascicular nucleus of the thalamus to acute myocardial ischaemia induced by selective coronary artery occlusion and the effects of midazolam on the response in rats.

Methods

The left anterior descending branch of the coronary artery was instrumented with a snare occluder in anaesthetized Sprague-Dawley rats. A single-barrel glass microelectrode was used for recording the unit discharges of the neuron in the parafascicular nucleus. The neuron responding only to noxious somatic stimulation was further examined for the response to coronary artery occlusion. Once the effect of coronary artery occlusion on the discharges was detected, the pharmacological effects of midazolam and flumazenil were examined.

Results

It was observed that the discharge rate of the neuron was markedly increased following coronary artery occlusion. Midazolam attenuated the increase in the discharges of the neuron induced by coronary artery occlusion (P < 0.05). The effect of midazolam was reversed by flumazenil.

Conclusions

The parafascicular nucleus is involved in the modulation of cardiac nociception and midazolam possesses antinociceptive property in modulating cardiac pain.

Type
Original Article
Copyright
Copyright © European Society of Anaesthesiology 2008

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