Abstract: (16646 Views)
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.