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. 1974 Jul;51(3):359–365. doi: 10.1111/j.1476-5381.1974.tb10670.x

On the mechanism of action of clonidine

Effects on single central neurones

Caroline Anderson, TW Stone
PMCID: PMC1776763  PMID: 4451750

Abstract

1 Noradrenaline and clonidine were applied by microiontophoresis to single neurones in the cerebral cortex and medullary reticular formation of anaesthetized rats.

2 Of a total of 247 neurones studied, 79% of medullary units and 60% of cortical units responded in the same manner to both noradrenaline and clonidine. The usual response was a depression of neuronal firing rate.

3 It proved possible to antagonize some responses to both substances by the microiontophoresis of bulbocapnine, whilst leaving unaffected similar responses to 5-hydroxytryptamine.

4 On 13% of the cells, clonidine produced an increase of firing rate. This effect could not be attributed to a post-synaptic antagonism of tonically released endogenous noradrenaline, but may indicate a presynaptic action of clonidine, reducing noradrenaline release.

5 These observations are thought to support the idea that clonidine may have an agonist action on noradrenaline receptors in the brain.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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