Clonidine inhibits itch-related response through stimulation of α(2)-adrenoceptors in the spinal cord in mice.
Summary of "Clonidine inhibits itch-related response through stimulation of α(2)-adrenoceptors in the spinal cord in mice."
The present study investigated whether clonidine - an α(2)-adrenoceptor agonist known to relieve pain - is able to suppress itch-related behavior in mice. An intraplantar injection of serotonin induced biting (an itch-related response), which was inhibited by intraperitoneal and intrathecal, but not intraplantar or intracisternal, clonidine injections. The effect of intrathecal clonidine was inhibited by intrathecal injections of phentolamine (a non-selective α-adrenoceptor antagonist) and yohimbine (a selective α(2)-adrenoceptor antagonist), but not by prazosin (a selective α(1)-adrenoceptor antagonist). The effect of intraperitoneal clonidine was also inhibited by intrathecal yohimbine. These results suggest that clonidine is an effective antipruritic agent and that the effect is mainly mediated by the stimulation of α(2)-adrenoceptors in the dorsal horn.
Affiliation
Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan.
Journal Details
This article was published in the following journal.
Name: European journal of pharmacology
ISSN: 1879-0712
Pages: 215-9
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20951695
- DOI: http://dx.doi.org/10.1016/j.ejphar.2010.10.011
Medical and Biotech [MESH] Definitions
Subliminal Stimulation
Stimulation at an intensity below that where a differentiated response can be elicited.
Evoked Potentials, Motor
The electrical response evoked in a muscle or motor nerve by electrical or magnetic stimulation. Common methods of stimulation are by transcranial electrical and TRANSCRANIAL MAGNETIC STIMULATION. It is often used for monitoring during neurosurgery.
Evoked Potentials, Auditory
The electric response evoked in the CEREBRAL CORTEX by ACOUSTIC STIMULATION or stimulation of the AUDITORY PATHWAYS.
Evoked Potentials, Visual
The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.
Clonidine
An alpha-2 adrenergic agonist that crosses the blood-brain barrier. Clonidine acts centrally by reducing sympathetic tone, resulting in a fall in diastolic and systolic blood pressure and a reduction in heart rate. It also acts peripherally, and this peripheral activity may be responsible for the transient increase in blood pressure seen during rapid intravenous administration. (From Martindale, the Extra Pharmacopoeia, 30th ed, p350)
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