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.