Pharmacological functional MRI on regional cerebral responses to central analgesics / 中国医学影像技术

ABSTRACT

Objective To investigate the regional cerebral stimulation after central analgesics nasal spray and its mechanism with pharmacological functional magnetic resonance imaging (phfMRI). Methods Eighteen healthy right-handed volunteers participated. Butorphanol tartrate nasal spray was used as the experiment agent. Ethological experiment was carried out to record the participants' subjective feeling and the onset time of the analgesics, followed by the functional MRI (fMRI) scan two weeks later. Block design was adopted. Two phases of fMRI scan were performed at 7 min and 25 min after the nasal spray, respectively. Participants were also given pain stimulation in the dorsum of hand during the fMRI scanning. The data were post-processed with Matlab 6.5 and SPM 2. Results ①Onset time of butorphanol tartrate was 15-35 min after nasal spray administration, which was consistent with its concentration-time curve. ②After nasal spray, activations were observed in the cerebral cortex, including frontal lobe (orbitofrontal gyrus, medial frontal gyrus, superior frontal gyrus), temporal lobe (insula, middle temporal gyrus, inferior temporal gyrus), parietal lobe (precuneal gyrus), limbic system (anterior cingulate gyrus, middle cingulate gyrus, hippocampus, parahippocampal gyrus);subcortical region (globus pallidus) and cerebellum (6-9 of cerebellar cortex, cerebellar peduncle, vermis). ③The number and activation intensity of the second phase were more obvious than those of the first phase (P<0.01). Conclusion The feasibility of phfMRI study on cerebral stimulation and the mechanism of nasal spray is demonstrated. The study of butorphanol tartrate further validates the main distribution of opioid receptors in the central nervous system and the possible mechanism of central analgesia.