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: 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 diff...

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...

‎ 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 were in...

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...

Ultra-low doses of non-selective α2-adrenoceptor antagonists augment acute spinal morphine antinociception and block morphine tolerance; however, the receptor involved in mediating these effects is currently unknown. Here, we used tail flick and paw pressure tests on the rat to investigate the acute analgesic and tolerance-inducing effects of spinal morphine and norepinephrine alone or in combi...

BACKGROUND The development of analgesic tolerance following chronic morphine administration can be a significant clinical problem. Preclinical studies demonstrate that chronic morphine administration induces spinal gliosis and that inhibition of gliosis prevents the development of analgesic tolerance to opioids. Many studies have also demonstrated that ultra-low doses of naltrexone inhibit the ...