Pharmacological FMRI: measuring opioid effects on the BOLD response to hypercapnia.

摘要: Opioid binding to the cerebral blood vessels may affect vascular responsiveness and hence confound interpretation of oxygen level-dependent (BOLD) responses, which are usually interpreted as neuronal in origin. varies different brain regions. It is unclear whether opioids alter neurovascular coupling, or their effects purely neuronal. This study used BOLD functional magnetic resonance imaging (FMRI) investigate effect a lopioid agonist remifentanil, on cerebrovascular CO2 reactivity (being one component coupling). Hypercapnic challenges were delivered human volunteers, while controlling potential opioid-induced respiratory depression. The signal increase hypercapnia was compared before during remifentanil administration. Remifentanil shown not have generalised vasculature. However, it caused significant reduction positive response bilateral primary sensorimotor cortices, extrastriate visual areas, left insula, caudate nucleus, inferior temporal gyrus. We conclude that does modulate reactivity, we saw no difference areas with high opioid receptor densities. did however see focal related motor control putative task activation, be changes activity sedative remifentanil. Our method levels effectively mitigated depression allowed comparison over similar range levels. suggest methodology should when investigating other potentially vasoactive compounds FMRI.