Effect of Morphine on c-fos Gene Expression Induced by Electrical Stimulation of Saphenous Nerve in the Anterior Cingulate Gyrus Neurons of Rats

Objective To investigate whether noxious somatic stimulation could induce changes in c-fos gene expression in the anterior cingulate gyrus(ACG)neurons and the effect of morphine on the changes.Methods The expression of Fos protein in ACG neurons was detected by immunohistochemistry at different times after electrical stimulation of saphenous nerve(SN),and the effect of subcutaneously injected morphine on the expression of Fos protein was determined.Results The expression Fos protein in ACG neurons significantly increased 30 minutes after the electrical stimulation of SN,reached the peak after 60 minutes,and began to decrease after 120 minutes.After subcutaneous injection of morphine,the increased expression of Fos protein induced by noxious electrical stimulation in ACG neurons was inhibited.Conclusion Noxious electrical stimulation of SN could increase the expression of Fos protein in ACG neurons in a time-dependent manner,and the increased expression of Fos protein is inhibited by morphine,suggesting that ACG is one of the representative areas of SN and can receive the nociceptive afferent information from SN.