in the present study, interactive effects of d1 and d2 dopamine receptors antagonists and different periods of lithium pretreatment on morphine dependence in mice have been investigated. this study was designed to investigate whether the hypothesis that lithium and dopaminergic mechanisms via their effects on phosphoinositide pathways and calcium flux could influence morphine withdrawal respons...

Medicinal use of the opium poppy (Papaver somniferum L) has ancient history, but the isolation of morphine was not described until the early nineteenth century. Morphine is the most important alkaloid of opium poppy in the last 50 years. In the morphine pathway has been reported to generate morphine in this species, CODM has a crucial role as the gene coding the enzyme respons...

We have evaluated the effects of lumbar extradural morphine and lignocaine on the ventilatory response to carbon dioxide. Twenty-four female patients were allocated randomly to receive extradural morphine 2 mg (group M), 2% lignocaine 10 ml (group L) or a combination of morphine 2 mg and 2% lignocaine 10 ml (group ML). On the day before surgery, resting ventilatory values including minute volum...

In contrast to the rapid development of tolerance to morphine in CD-1 mice, tolerance is not seen in 129/SvEv mice implanted with morphine pellets or given daily morphine injections for 5 days. Similarly, the progressive and complete loss of analgesia in CD-1 mice seen with repeated dosing of the delta ligand [D-Pen2, D-Pen5]enkephalin is not observed in 129/SvEv mice. In contrast, tolerance de...

Morphine was used as a remedy for the control of diarrhea centuries before it's sedative-analgesic effect was discovered. Although several mechanisms have been proposed for the morphine-induced inhibition of gastrointestinal transit (OIT), the exact mechanism has not yet been identified. On this basis the possible involvement of the dopaminergic system in morphine-induced inhibition of tra...

The glycine site (MRZ 2/570 and L-701,324), and uncompetitive (MRZ 2/579) NMDA receptor antagonists inhibited morphine-produced behaviors related to drug-abuse. The expression of morphine dependence was blocked by pretreatment with all three compounds (3–7.5 mg/kg); the effects of glycine/NMDA antagonists were not dose-dependent. Mice which were morphine-free for 3 days still displayed a signif...

BACKGROUND An increased and prolonged duration of pain relief after morphine administration has been found in elderly patients. Whether this is due to alterations in pharmacokinetics, receptor binding profile or other factors remains unsolved. The aims were to elucidate the pharmacokinetics after intravenous administration of morphine and oxycodone in elderly patients older than 70 years. MET...

OBJECTIVES Morphine dependence (MD) potently protects heart against ischemia reperfusion (IR) injury through specific signaling mechanisms, which are different from the pathways involved in acute morphine treatment or classical preconditioning. Since opioid receptor density changes post cerebral ischemia strongly correlated with brain histological damage, in the present study, we tried to eluci...

Background: It has been known that Brain-Derived Neurotrophic Factor (BDNF) is involved in neural survival and long term memory (LTM). Here we hypothesized that BDNF as a potent neurotrophic factor might modulate amnestic effect induced by morphine. Objectives: The aim of this study was to examine whether infusion of exogenous BDNF in the CA1 regions of the dorsal hippocampi could ameliorate me...

Opioids provide powerful analgesia but also efficacy-limiting adverse effects, including severe nausea, vomiting, and respiratory depression, by activating l-opioid receptors. Preclinical models suggest that differential activation of signaling pathways downstream of these receptors dissociates analgesia from adverse effects; however, this has not yet translated to a treatment with an improved ...