the effects of locus coeruleus electrical stimulation on brain waves of morphine dependent rats

introduction: opiates cause dependency via affect on central nervous system. locus coeruleus nucleus is a main group of noradrenergic neurons in the brain that plays an important role in the expression of opioid withdrawal signs. during opioid withdrawal, brain waves change in addition to physical and behavioral signs. in this study, we examined the effects of locus coeruleus electrical stimulation on brain waves of morphine dependent rats. methods: ten male wistar rats were given intraplantar injections of increasing doses of morphine for 9 days. on day 10 after induction of anesthesia, electroencephalogram (eeg) recording was done. the eeg recording was also continued after intraplantar injection of naloxone. in the next step, rats were placed in stereotaxic apparatus and following the electrical stimulation of locus coeruleus, eeg was also recorded. results: naloxone injection increased the power of delta waves (p<0.05) and decreased the power of theta waves (p<0.01). the power of alpha waves and beta waves had not significant changes following naloxone administration. electrical stimulation of locus coeruleus, decreased the power of delta waves(p<0.01) and increased the power of alpha waves (p<0.05) , but did not change the power of theta and beta waves. the eeg total power increased during the withdrawal and decreased following electrical stimulation of locus coeruleus. conclusion: the changes in eeg due to naloxone administration which reversed toward the basal level after electrical stimulation of locus coeruleus suggests that violence of the locus coeruleus activity by its electrical stimulation in withdrawal stage, results in a compensative reaction in order to attenuation the effects of hyperactivity of the locus coeruleus.