OBJECTIVES Dependence and tolerance to opioid analgesics are major problems limiting their clinical application. α-Terpineol is a monoterpenoid alcohol with neuroprotective effects which is found in several medicinal plants such as Myrtus communis, Laurus nobilis, and Stachys byzantina. It has been shown that some of these medicinal plants such as S. byzantina attenuate dependence and tolerance...

Glycyl-glutamine (Gly-Gln; beta-endorphin(30-31)) is an endogenous dipeptide synthesized from beta-endorphin(1-31). Previous investigations have shown that Gly-Gln inhibits the cardiovascular and respiratory depression caused by morphine and beta-endorphin(1-31), but it does not interfere with opioid analgesia. In this study, we tested whether Gly-Gln administration would influence morphine-ind...

AIM To investigate the effects of morphine dependence and withdrawal on the concentrations of neurosteroids in rat brain. METHODS A method of simultaneous quantification of neurosteroids by gas chromatography-mass spectrometry (GC-MS) had been established. RESULTS The chronic morphine administration (ip) resulted in a marked decrease in the brain concentrations of pregnenolone (PREG), proge...

mice were rendered tolerant and dependent to morphine by subcutaneous injection of morphine over a period of 5 days. the effects of acute and chronic administration of dihydropyridine calcium channel antagonist nifedipine on the development of tolerance and naloxone-precipitated morphine withdrawal signs were investigated. a single injection of nifedipine proved to be effective in inhibiting so...

Acute morphine withdrawal is considered to be the physical manifestation of dependence, emerging when morphine administration is stopped or after the administration of an opiate antagonist, such as naloxone. Gabapentin, which is an antiepileptic, agent, enhances the analgesic effect of morphine in healthy volunteers, but its effect on morphine dependence and withdrawal signs has not determined ...

Although morphine induces both analgesia and dependence through mu-opioid receptors (MORs), the respective contributions of the intracellular effectors engaged by MORs remain unknown. To examine the contribution of G-protein-gated inwardly rectifying K(+) (GIRK, Kir3) channels to morphine dependence and analgesia, we quantified naloxone-precipitated withdrawal behavior and morphine analgesia us...

Physical dependence on morphine is evidenced by the withdrawal syndromes, including body weight loss, which are induced by the discontinuation of morphine exposure or by the treatment with naloxone, an opioid receptor antagonist. The present study was designed to examine whether the elevation of serum corticosterone (SCS) level induced by naloxone-precipitated morphine withdrawal was a useful i...

The mechanisms by which morphine-induced analgesia and tolerance and physical dependence on morphine arise have been the subject of intense study, and much work has pointed to the involvement of cAMP-mediated events in the neuroadaptive phenomena leading to morphine tolerance and/or dependence. We overexpressed an opioid receptor-stimulatable form of adenylyl cyclase (type 7) in the central ner...

Learning and memory have been suggested to be important in the development of opiate addiction. Based on the recent findings that calcium/calmodulin-dependent protein kinase II (CaMKII) is essential in learning and memory processes, and morphine treatment increases CaMKII activity in hippocampus, the present study was undertaken to examine whether inhibition of hippocampal CaMKII prevents morph...