Morphine is a potent opioid analgesic. However, the repeated use of morphine causes tolerance and hyperalgesia. Neuroinflammation has been reported to be involved in morphine tolerance and withdrawal-induced hyperalgesia. The complement system is a crucial effector mechanism of immune responses. The present study investigated the roles of complement factor C5a and C5a receptor (C5aR) in the dev...

Objective: In the present study, the effects of aqueous saffron extract (Crocus sativus L.) on the acquisition and reinstatement of morphine-induced conditioned place preference (CPP) in mice were investigated. Materials and Methods: Subcutaneous administration of morphine (40 mg/kg for four days) produced place preference. Intraperitoneal administration of aqueous extract (40 and 80 mg/kg for ...

BACKGROUND Chronic morphine exposure creates dependence and, upon cessation, withdrawal symptoms. Studies indicate the phosphodiesterase type 5 (PDE5) inhibitor sildenafil may provide centrally mediated benefits against withdrawal, and therefore, this study evaluated morphine withdrawal signs in dependent mice with and without sildenafil treatment. METHOD Dependence was induced by repeated tr...

We would like to thank Professor Parsons for his interest and comments concerning our manuscript ‘‘Cytotoxicity of Oxycodone and Morphine in Human Neuroblastoma and Mouse Motoneuronal Cells: A Comparative Approach’’ [1]. We totally agree with Parsons that the choice of appropriate cell model is of paramount importance in in vitro drug toxicity testing [2]. Moreover, using at least two cell line...

BACKGROUND Mammalian cells synthesize morphine and the respective biosynthetic pathway has been elucidated. Human neutrophils release this alkaloid into the media after exposure to morphine precursors. However, the exact role of endogenous morphine in inflammatory processes remains unclear. We postulate that morphine is released during infection and can be determined in the serum of patients wi...

OBJECTIVE To determine synovial concentrations of morphine after intravenous regional limb perfusion (IVRLP) with morphine or morphine in combination with gentamicin in clinically healthy, standing sedated horses. STUDY DESIGN Experimental. ANIMALS Adult horses (n = 6). METHODS IVRLP was performed using 0.1 mg/kg morphine (M) in standing sedated horses. After a 3-week washout period, IVRL...

BACKGROUND Acetaminophen is commonly used for the management of perioperative pain. However, there is a marked discrepancy between the extent to which acetaminophen is used and the available evidence for an analgesic effect after major surgery. The aim of this systematic review is to determine the morphine-sparing effect of acetaminophen combined with patient-controlled analgesia (PCA) with mor...

The effects of repeated administration of morphine and methadone, followed by a challenge dose of either morphine or methadone were examined ex vivo in rat frontal cortical slices that were prepared 1 h after final drug administration. Morphine challenge dose (5 mg/kg), administered 14 days after the end of repeated morphine pretreatment (10 mg/kg, administered 7 times) decreased both the AMPA/...

BACKGROUND The feasibility and clinical implication of drug monitoring of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) need further investigation. This study aimed to determine what predicts serum concentrations of morphine in cancer patients receiving continuously intravenous morphine, the relationships between serum concentration of morphine/its metabolites and urin...

BACKGROUND/PURPOSE We previously showed that subsequent intrathecal (i.t.) injection of resveratrol (30 μg) significantly reverses morphine-evoked neuroinflammation in morphine-tolerant rats. The present study examined the underlying mechanism. METHODS Male Wistar rats were implanted with two i.t. catheters, one of which was connected to a miniosmotic pump and used for morphine (15 μg/h) or s...