Hippocampus as part of the limbic system plays an important role in abused drugs-induced memory. The role of glutamate receptor within the hippocampal CA1 area in morphine-induced memory has also been postulated. Previous studies indicated that glutamate receptors exert their effects in part through the release of nitric oxide (NO). In the present study, the effects of intra-CA1 area injections...

Chronic pain, including cancer-related pain, is a pain condition often caused by inflammation or dysfunctional nerves. Chronic pain treatment poses a significant health care challenge, where opioids especially morphine are widely used and patients often develop tolerance over time with aggravated pain. microRNA (miRNA) is known to play important roles in regulating gene expressions in the nervo...

Objective(s): We aimed to examine association of gene expression of MOR1 and GluN1 at mRNA level in the lumbosacral cord and midbrain with morphine tolerance in male Wistar rats. Materials and Methods: Analgesic effects of morphine administrated intraperitoneally at doses of 0.1, 1, 5 and 10 mg/kg were examined using a hot plate test in rats with and without a history of 15 days morphine (10 mg...

(2008). Sexually dimorphic activation of the periaqueductal gray-rostral ventromedial medullary circuit during the development of morphine tolerance in the rat. ABSTRACT Previous studies have shown that tolerance develops to a greater degree in male compared to female rats. The midbrain periaqueductal gray (PAG), and its descending projections to the rostral ventromedial medulla (RVM), provides...

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...

Key pecking by 3 pigeons was maintained by a multiple fixed-ratio 10, fixed-ratio 30, fixed-ratio 90 schedule of food presentation. Components differed with respect to amount of reinforcement, such that the unit price was 10 responses per 1-s access to food. Acute administration of morphine, l-methadone, and cocaine dose-dependently decreased overall response rates in each of the components. Wh...

introduction: deficiency in mu opioid receptor signaling pathway is partially responsible for morphine tolerance. this deficiency may be due to uncoupling of opioid receptors and related g proteins, which in turn, it may be caused by their structural changes such as phosphorylation or by decreasing their abundance. in this study, we tried to investigate the effect of chronic administration of m...

OBJECTIVES Morphine is widely used to treat chronic pain. However, its utility is hindered by the development of tolerance to its analgesic effects. Despite the renowned beneficial effects of physical exercise on cognitive functions and signs of morphine withdrawal in morphine-dependent rats, little is known about the roles of voluntary and forced exercises in tolerance to analgesic effect of m...

Antagonists of the NMDA type of excitatory amino acid (EAA) receptor attenuate or reverse the development of tolerance to the analgesic effects of the mu opioid agonist morphine, the delta-1 opioid agonist DPDPE but not the kappa-1 agonist U50,488H or the kappa-3 agonist naloxone benzoylhydrazone. The role of the AMPA subtype of EAA receptor in analgesic tolerance was examined using LY293558, a...

The role of glutamate receptor within the nucleus accumbens in morphine tolerance has been postulated. Previous studies have reported that glutamate receptors exert their effects in part through the release of nitric oxide (NO). In the present study the effects of intra-accumbal injections of L-arginine (0.3, 1, and 3 ?g/rat), the NO precursor and L-NAME (0.3, 1, and 3 ?g/rat), the NOS inhibito...