AIM OF STUDY: To investigate the effect of mitragynine after chronic morphine treatment on cyclic AMP (cAMP) level and mRNA expression of mu-opioid receptor (MOR) in human neuroblastoma SK-N-SH cell.
METHOD AND MATERIALS: Mitragynine was isolated from the Mitragyna speciosa plant using the acid-base extraction method. The cAMP level upon forskolin stimulation in the cells was determined using the Calbiochem(®) Direct Immunoassay Kit. The mRNA expression of the MOR was carried out using quantitative RT-PCR.
RESULT: Cotreatment and pretreatment of morphine and mitragynine significantly reduced the production of cAMP level at a lower concentration of mitragynine while the higher concentration of this compound could lead to the development of tolerance and dependence as shown by the increase of the cAMP level production in foskolin stimulation. In MOR mRNA expression study, cotreatment of morphine with mitragynine significantly reduced the down-regulation of MOR mRNA expression as compared to morphine treatment only.
CONCLUSION: These finding suggest that mitragynine could possibly avoid the tolerance and dependence on chronic morphine treatment by reducing the up-regulation of cAMP level as well as reducing the down-regulation of MOR at a lower concentration of mitragynine.
SETTING: Hospital surgical ward.
SUBJECTS: Women (107 Indian, 184 Malay, and 750 Han Chinese) undergoing total hysterectomy surgery.
METHODS: Morphine consumption, preoperative pain, and postoperative pain were evaluated in relation to genetic variability comprising 19 single-nucleotide polymorphisms (SNPs) in 14 genes involved in glial activation, inflammatory signaling, and neuronal regulation, plus OPRM1 (1 SNP) and COMT (3 SNPs).
RESULTS: Pre- and postoperative pain and age were associated with increased and decreased morphine consumption, respectively. In Chinese patients, only 8% of the variability in consumption could be explained by these nongenetic and genetic (BDNF, IL1B, IL6R, CRP, OPRM1, COMT, MYD88) factors. However, in Indian patients, 41% of morphine consumption variability could be explained by age (explaining <3%) and variants in OPRM1 rs1799971, CRP rs2794521, TLR4 rs4986790, IL2 rs2069762, COMT rs4818, TGFB1 rs1800469, and IL6R rs8192284 without controlling for postoperative pain.
CONCLUSIONS: This is the highest known value reported for genetic contributions (38%) to morphine use in the acute postoperative pain setting. Our findings highlight the need to incorporate both genetic and nongenetic factors and consider ethnicity-dependent and nonadditive genotypic models in the assessment of factors that contribute to variability in opioid use.
OBJECTIVE: This study sought to detect CYP2B6 and OPRM1 variants and their genotypes, as major contributors to inter-variability in methadone responsiveness and methadone dose requirements.
METHODS: We carried out a prospective experimental one-phase pharmacogenetic study in four addiction clinics in Malaysia. Patients on stable methadone maintenance therapy were recruited. The prevalence of the CYP2B6 and OPRM1 polymorphisms was determined using a nested polymerase chain reaction (PCR), followed by genotyping. A two-step multiplex PCR method was developed to simultaneously detect the 26 SNPs in these two genes.
RESULTS: 120 males were recruited for this study. The patients were between 21and 59 years old, although the majority of the patients were in their 30s. C64T and G15631T in CYP2B6and G31A, G691C, and A118G in OPRM1 were found to be polymorphic, and the allelic frequencies of each were calculated. We further detected eight new haplotypes.
CONCLUSION: C64T and G15631T in CYP2B6and G31A, G691C, and A118G in OPRM1were found to be polymorphic. The new haplotypes may give a new insight on methadone clinics.
Materials and Methods: We examined RANKL expression in 39 patients (21 males, 18 females) by immunohistochemistry. Four patients (10%) were presented with tumor recurrence, eight patients (20%) were complicated with lung metastasis, and two patients (5%) were presented with both recurrence and lung metastasis. Positive RANKL expression was assessed according to a scoring system evaluating the percentage of the immunostained epithelial area and the staining intensity. The cumulative score was calculated to determine the final score value. Data were analyzed using PASW version 18.0 and independent t-test between nonrecurrence/recurrence groups, and nonlung metastasis/lung metastasis groups. Significance was set at P < 0.05.
Results: Thirty-two patients (82%) scored 3 in RANKL-staining percentage from whole stromal cell population (>75%), 6 patients scored 2, and 1 patient scored 1. Nine patients (23%) scored 3 in RANKL-staining intensity (most intense), 19 patients (48%) scored 2, and 11 patients (29%) scored 1. Twenty six patients (67%) had strong RANKL expression (total score of 5-6), 12 patients (31%) showed moderate score (3-4) whereas only 1 patient (2%) showed weak RANKL expression. Together, the mean value of RANKL-staining percentage was 2.79, intensity 1.95 and the total score 4.77. The mean RANKL-staining percentage between recurrence and nonrecurrence groups was statistically significant (P = 0.009). There was no significant difference in the mean staining intensity and total score between nonrecurrence and recurrence groups, and staining percentage staining intensity and a total cumulative score of RANKL expression between lung metastasis and nonlung metastasis groups.
Conclusion: RANKL expression is generally high in Stage III GCT and is a reliable prognostic marker in predicting the risk of local recurrence however not in lung metastasis.
Objectives: This study aimed to determine the specific brain region that is responsive to KOPr treatment following polydrug dependence.
Materials and Methods: The polydrug-dependent mice model was developed using conditioned place preference (CPP) method. Following successful withdrawal phase, the mice were treated with 0.3 mg/kg buprenorphine and 1.0 mg/kg naltrexone. Four brain regions (hippocampus, prefrontal cortex, amygdala, and striatum) were investigated using immunohistochemistry technique. This is to quantify the changes in KOPr expression in each major brain region that was primarily involved in addiction neurocircuits of many substances. Unpaired Student's t test was used to analyze all results, where P < 0.05 is considered significant.
Results: The results showed that treatment with buprenorphine and naltrexone successfully attenuated relapse in 60% of mice (n = 14). A significant upregulation of KOPr was detected in striatum at the end of post-withdrawal phase (P < 0.01, n = 12). This treatment successfully suppressed KOPr in striatum (P < 0.001, n = 12), which supports the positive results seen in the CPP setting. No significant changes were observed in other brain regions studied.
Conclusion: The hyperactivity of striatum suggests that the affected brain region following KOPr antagonist treatment is the region that primarily controls the drug rewarding activity, in which nucleus accumbens is located. This indicates that manipulation of KOPr system is one of the potential targets to treat morphine- or methamphetamine-dependence problem.
AIM OF THE STUDY: This study aimed to elucidate the possible mechanism(s) of antidiarrhoeal activity of methanol leaf extract of Combretum hypopilinum (MECH) in mice.
MATERIALS AND METHODS: Phytochemical screening and acute toxicity study were conducted according to standard methods. Adult mice were orally (p.o) administered distilled water (10 ml/kg), MECH (1000 mg/kg) and loperamide (5 mg/kg). The probable mechanisms of antidiarrhoeal activity of MECH were investigated following pretreatment with naloxone (2 mg/kg, subcutaneously), prazosin (1 mg/kg, s.c), yohimbine (2 mg/kg, intraperitoneally), propranolol (1 mg/kg, i.p), pilocarpine (1 mg/kg, s.c) and isosorbide dinitrate (150 mg/kg, p.o) 30 min before administration of MECH (1000 mg/kg). The mice were then subjected to castor oil-induced intestinal motility test.
RESULTS: The oral median lethal dose (LD50) of MECH was found to be higher than 5000 mg/kg. There were significant (p