Richard G. Wise1, Anna Jolly2, C
John Evans1, Kevin Murphy1, Fernando Zelaya3,
David Lythgoe3, Kyle Pattinson4, Judith E. Hall2
1CUBRIC, School of Psychology, Cardiff
University, Cardiff, United Kingdom; 2Department of Anaesthetics and
Intensive Care Medicine, School of Medicine, Cardiff University, Cardiff,
United Kingdom; 3Centre for Neuroimaging Sciences, Institute of
Psychiatry, King's College, London, United Kingdom; 4Nuffield
Department of Anaesthetics, Oxford University, Oxford, United Kingdom
We
show that pulsed ASL is sensitive to opioid administration in the human
brain. We measured the effects of a μ-opioid (remifentanil) on regional
CBF. By training volunteers to maintain their breathing, we mitigated the
global CBF increases arising from increased arterial carbon dioxide levels
that result from opioid-induced respiratory depression. Significant localised
opioid-induced CBF increases were observed in the thalamus and brainstem,
whereas, decreases were observed in the putamen: all areas rich in opioid
receptors. The regionally specific nature of the opioids effect on CBF will
be useful in interpreting opioid-related changes in task-related activity
with FMRI.
Keywords