Article

The Effect of Clonidine Infusion on Distribution of Regional Cerebral Blood Flow in Volunteers

University Department of Anesthesia and Intensive Care Medicine, CHU de Liege and CHR de la Citadelle, 4000 Liege, Belgium.
Anesthesia and analgesia (Impact Factor: 3.47). 04/2008; 106(3):899-909, table of contents. DOI: 10.1213/ane.0b013e3181619685
Source: PubMed

ABSTRACT

Through their action on the locus coeruleus, alpha2-adrenoceptor agonists induce rapidly reversible sedation while partially preserving cognitive brain functions. Our goal in this observational study was to map brain regions whose activity is modified by clonidine infusion so as to better understand its loci of action, especially in relation to sedation.
Six ASA I-II right-handed volunteers were recruited. Electroencephalogram (EEG) was monitored continuously. After a baseline H2(15)O activation scan, clonidine infusion was started at a rate ranging from 6 to 10 microg x kg(-1) x h(-1). A sequence of 11 similar scans was then performed at 8 min intervals. Plasma clonidine concentration was measured. Using statistical parametric mapping, we sought linear correlations between normalized regional cerebral blood flow (rCBF), an indicator of regional brain activity, and plasma clonidine concentration or spindle EEG activity.
Clonidine induced clinical sedation and EEG patterns (spindles) comparable to early stage nonrapid eye movement sleep. A significant negative linear correlation between clonidine concentration and rCBF or spindle activity was observed in the thalamus, prefrontal, orbital and parietal association cortex, posterior cingulate cortex, and precuneus.
The EEG patterns and decreases in rCBF of specific brain regions observed during clonidine-induced sedation are similar to those of early stage nonrapid eye movement sleep. Patterns of deactivated brain regions are also comparable to those observed during general anesthesia or vegetative state, reinforcing the hypothesis that alterations in the activity of a common network occur during these modified conscious states.

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Available from: Vincent Bonhomme
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    • "dies . The α2 - adrenergic agonist induces sedation through endogenous sleep pathways by its action on the locus ceruleus ( which has the highest presynaptic α2 - adrenergic receptor concentration ) that in turn decrease the afferent input to the thalamus and thus decrease thalamic activity ( Correa - Sales et al . , 1992 ; Nelson et al . , 2003 ; Bonhomme et al . , 2008 ) . In both human and animal studies , dexmedetomidine administration causes a clear decrease in global CBF ( Zornow et al . , 1990 ; Prielipp et al . , 2002 ; Drummond et al . , 2008 ; Fukuda et al . , 2013 ) , which some suggest arises from cerebral vasoconstriction ( Zornow et al . , 1990 ; Prielipp et al . , 2002 ) . The cerebrovasc"

    Full-text · Dataset · Sep 2015
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    • "dies . The α2 - adrenergic agonist induces sedation through endogenous sleep pathways by its action on the locus ceruleus ( which has the highest presynaptic α2 - adrenergic receptor concentration ) that in turn decrease the afferent input to the thalamus and thus decrease thalamic activity ( Correa - Sales et al . , 1992 ; Nelson et al . , 2003 ; Bonhomme et al . , 2008 ) . In both human and animal studies , dexmedetomidine administration causes a clear decrease in global CBF ( Zornow et al . , 1990 ; Prielipp et al . , 2002 ; Drummond et al . , 2008 ; Fukuda et al . , 2013 ) , which some suggest arises from cerebral vasoconstriction ( Zornow et al . , 1990 ; Prielipp et al . , 2002 ) . The cerebrovasc"

    Full-text · Dataset · Sep 2015
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    • "We observed a departure from slow and temporally correlated dynamics in frontal regions and in the thalamus. These areas strongly overlap with those where decreased metabolism under anesthesia was reported (Alkire et al., 1997; Kaisti et al., 2002; Kaisti et al., 2003; Schreckenberger et al., 2004; Laitio et al., 2007; Bonhomme et al., 2008). Breakdown of longrange temporal correlations was also reported in other unconscious brain states such as deep non-rapid eye movement (NREM) sleep (Tagliazucchi et al., 2013a). "
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    Full-text · Article · Sep 2015 · Journal of The Royal Society Interface
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