An individual variation study of electroacupuncture analgesia in rats using microarray.

The aim of the present study is to probe candidate genes which were involved in the electroacupuncture (EA) analgesia and to understand the molecular basis of the individual difference of EA analgesia in rats. We compared hypothalamus transcriptional profiles of responders with those of non-responders after 1 Hz EA treatment at ST36 acupoint for 1 hour by using oligonucleotide microarray. Responders and non-responders were determined by tail flick latency (TFL). A real-time quantitative RT-PCR was applied to validate the differential expressed genes. Our study provided a global hypothalamus transcriptional profile of EA analgesia in rats. We found that 63 and 3 genes were up- and down-regulated in the responder group, respectively. Half of the differentially expressed genes were classified into 9 functional groups which were ion transport, sensory perception, synaptogenesis and synaptic transmission, signal transduction, inflammatory response, apoptosis, transcription, protein amino acid phosphorylation and G-protein signaling. Glutamatergic receptors, ghrelin precursor, melanocortin 4 receptor (MC4-R) and neuroligin 1 were found to be up-regulated in the responder group which may become new targets for nociceptive study and deserve further investigation for developing new acupuncture therapy and intervention of pain modulation.