Introduction: In the Kindling-induced seizure model, low and repeated electrical or chemical stimulations, can elevate the neural network excitability and induce epileptiform seizures. Opioid receptors are widely distributed in different areas of the brain. On the other hand, morphine has paradoxical effects and induces elevation or alleviation of the pain sensation and excitability, at differe...

‎ Introduction: Controversial results have been reported about the effect of morphine and stress on learning and spatial memory in rodents. There are very few studies about the effects of ultra low doses of morphine on memory. In this study, effects of acute administration of low and usual doses of morphine on memory formation and retention in the presence and absence of repeated stress w...

Opioid agonists such as morphine have been found to exert excitatory and inhibitory receptor-mediated effects at low and high doses, respectively. Ultra-low doses of opioid antagonists (naloxone and naltrexone), which selectively inhibit the excitatory effects, have been reported to augment systemic morphine analgesia and inhibit the development of tolerance/physical dependence. This study inve...

Chronic morphine causes the mu opioid receptor (MOR) to switch its coupling from Gi/o to Gs, resulting in excitatory signaling via both Galphas and its Gbetagamma dimer. Ultra-low-dose naloxone (NLX) prevents this switch and attenuates opioid tolerance and dependence. This protective effect is mediated via a high-affinity interaction of NLX to a pentapeptide region in c-terminal filamin A (FLNA...

Introduction: Ultra low dose (ULD) morphine induces hyperalgesia which is mediated by excitatory Gscoupled opioid receptors. This study was designed to investigate the development of tolerance to hyperalgesic effect of morphine. Also we attempt to seek possible similarity, in view of Gs proteins, between hyperalgesic effect of ULD and hyperalgesic effect after tolerance to HD. Method: Male Wist...

Introduction: Uncoupling protein 2 (UCP2) in the inner mitochondrial membrane changes the activity of KATP channels and the cell excitability, probably by decreasing the ATP production. Given the expression of UCP2 in primary afferent neurons, and the importance of these channels in morphine-induced analgesia, genipin, an UCP2 inhibitor, may affect these processes, when administrated intratheca...