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1.
Osteoporos Int ; 29(12): 2645-2658, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30306226

ABSTRACT

By integrating the multilevel biological evidence and bioinformatics analyses, the present study represents a systemic endeavor to identify BMD-associated genes and their roles in skeletal metabolism. INTRODUCTION: Single-nucleotide polymorphism (SNP)-based genome-wide association studies (GWASs) have already identified about 100 loci associated with bone mineral density (BMD), but these loci only explain a small proportion of heritability to osteoporosis risk. In the present study, we performed a gene-based analysis of the largest GWASs in the bone field to identify additional BMD-associated genes. METHODS: BMD-associated genes were identified by combining the summary statistic P values of SNPs across individual genes in the two consecutive meta-analyses of GWASs from the Genetic Factors for Osteoporosis (GEFOS) studies. The potential functionality of these genes to bone was partially assessed by differential gene expression analysis. Additionally, the consistency of the identification of potential bone mineral density (BMD)-associated variants were evaluated by estimating the correlation of the P values of the same single-nucleotide polymorphisms (SNPs)/genes between the two consecutive Genetic Factors for Osteoporosis Studies (GEFOS) with largely overlapping samples. RESULTS: Compared to the SNP-based analysis, the gene-based strategy identified additional BMD-associated genes with genome-wide significance and increased their mutual replication between the two GEFOS datasets. Among these BMD-associated genes, three novel genes (UBTF, AAAS, and C11orf58) were partially validated at the gene expression level. The correlation analysis presented a moderately high between-study consistency of potential BMD-associated variants. CONCLUSIONS: Gene-based analysis as a supplementary strategy to SNP-based genome-wide association studies, when applied here, is shown that it helped identify some novel BMD-associated genes. In addition to its empirically increased statistical power, gene-based analysis also provides a higher testing stability for identification of BMD genes.


Subject(s)
Bone Density/genetics , Osteoporosis/genetics , Polymorphism, Single Nucleotide , Databases, Genetic , Gene Expression Profiling/methods , Gene Expression Regulation/physiology , Genetic Predisposition to Disease , Genome-Wide Association Study/methods , Humans
2.
Zhonghua Yu Fang Yi Xue Za Zhi ; 52(5): 511-516, 2018 May 06.
Article in Chinese | MEDLINE | ID: mdl-29747343

ABSTRACT

Objective: To investigate the association between tea consumption and lung cancer risk in Chinese males. Methods: Tea consumption and incident lung cancer cases were collected on a biennial basis among males in Kailuan Cohort during 2006-2015. Up to 31st December 2015, a total of 103 010 male candidates from the Chinese Kailuan Male Cohort Study were enrolled in the present study. Cox proportional hazards regression model was used to evaluate the association between tea consumption and risk of lung cancer in males. Results: The age of male candidates was (51.3±13.4)years old. There were 828 810.74 person-years of follow-up and 8.91 years of median follow-up period. During the follow-up, 964 lung cancer cases were identified. In male, the rate of never cosumers, tea drinkers (<4/week) and tea drinkers (≥4/week) were 58.17%(n=59 926), 24.04%(n=24 765) and 17.78%(n=18 319), respectively. After adjustment for potential confounding factors, HR (95%CI) of lung cancer for subjects with tea drinkers (<4/week) and tea drinkers (≥4/week) were 0.80 (0.63-1.02) and 1.02 (0.80-1.30), respectively, as compared with never cosumers. The results showed no significant association with lung cancer. Stratification analysis and sensitivity analysis showed no significant changes. Conclusion: Our study has not found that tea consumption is significantly associated with the risk of male lung cancer.


Subject(s)
Lung Neoplasms/epidemiology , Adult , China/epidemiology , Cohort Studies , Female , Humans , Male , Middle Aged , Proportional Hazards Models , Prospective Studies , Risk , Risk Factors , Tea
3.
Br J Dermatol ; 179(5): 1088-1094, 2018 11.
Article in English | MEDLINE | ID: mdl-29723931

ABSTRACT

BACKGROUND: Many antihypertensive drugs (ADs) are photosensitizing, heightening reactivity of the skin to sunlight. Photosensitizing ADs have been associated with lip cancer, but whether they impact the risk of cutaneous squamous cell carcinoma (cSCC) is unknown. OBJECTIVES: To examine the association between AD use and cSCC risk among a cohort of non-Hispanic white individuals with hypertension enrolled in a comprehensive integrated healthcare delivery system in northern California (n = 28 357). METHODS: Electronic pharmacy data were used to determine exposure to ADs, which were classified as photosensitizing, nonphotosensitizing or unknown, based on published literature. We identified patients who developed a cSCC during follow-up (n = 3010). We used Cox modelling to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Covariates included age, sex, smoking, comorbidities, history of cSCC and actinic keratosis, survey year, healthcare utilization, length of health plan membership and history of photosensitizing AD use. RESULTS: Compared with nonuse of ADs, risk of cSCC was increased with ever having used photosensitizing ADs (aHR = 1·17, 95% CI 1·07-1·28) and ever having used ADs of unknown photosensitizing potential (aHR = 1·11, 95% CI 1·02-1·20), whereas no association was seen with ever having used nonphotosensitizing ADs (aHR = 0·99; 95% CI 0·91-1·07). Additionally, there was a modest increased risk with an increased number of prescriptions for photosensitizing ADs (aHR = 1·12, 95% CI 1·02-1·24; aHR = 1·19, 95% CI 1·06-1·34; aHR = 1·41, 95% CI 1·20-1·67 for one to seven, eight to 15 and ≥ 16 fills, respectively). CONCLUSIONS: These findings provide moderate support for an increased cSCC risk among individuals treated with photosensitizing ADs.


Subject(s)
Antihypertensive Agents/adverse effects , Carcinoma, Squamous Cell/epidemiology , Hypertension/drug therapy , Photosensitizing Agents/adverse effects , Skin Neoplasms/epidemiology , Sunlight/adverse effects , Aged , California/epidemiology , Carcinoma, Squamous Cell/etiology , Drug Prescriptions/statistics & numerical data , Female , Follow-Up Studies , Humans , Male , Middle Aged , Skin Neoplasms/etiology , White People
4.
Genet Mol Res ; 14(1): 886-97, 2015 Feb 02.
Article in English | MEDLINE | ID: mdl-25730027

ABSTRACT

Ganoderma mushroom is one of the most prescribed traditional medicines and has been used for centuries, particularly in China, Japan, Korea, and other Asian countries. In this study, different strains of Ganoderma spp and the genetic relationships of the closely related strains were identified and investigated based on the V4-V6 region of mitochondrial small subunit ribosomal DNA of the Ganoderma species. The sizes of the mitochondrial ribosomal DNA regions from different Ganoderma species showed 2 types of sequences, 2.0 or 0.5 kb. A phylogenetic tree was constructed, which revealed a high level of genetic diversity in Ganoderma species. Ganoderma lucidum G05 and G. eupense G09 strains were clustered into a G. resinaceum group. Ganoderma spp G29 and G22 strains were clustered into a G. lucidum group. However, Ganoderma spp G19, G20, and G21 strains were clustered into a single group, the G. lucidum AF214475, G. sinense, G. strum G17, G. strum G36, and G. sinense G10 strains contained an intron and were clustered into other groups.


Subject(s)
DNA, Mitochondrial/genetics , DNA, Ribosomal/genetics , Ganoderma/genetics , Genetic Variation , China , Ganoderma/classification , Humans , Japan , Medicine, Chinese Traditional , Phylogeny , Republic of Korea
5.
Asian-Australas J Anim Sci ; 28(4): 530-7, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25656200

ABSTRACT

The objective of this study was to evaluate the in vitro effects of flavonoid-rich plant extracts (PE) on ruminal fermentation characteristics and methane emission by studying their effectiveness for methanogenesis in the rumen. A fistulated Holstein cow was used as a donor of rumen fluid. The PE (Punica granatum, Betula schmidtii, Ginkgo biloba, Camellia japonica, and Cudrania tricuspidata) known to have high concentrations of flavonoid were added to an in vitro fermentation incubated with rumen fluid. Total gas production and microbial growth with all PE was higher than that of the control at 24 h incubation, while the methane emission was significantly lower (p<0.05) than that of the control. The decrease in methane accumulation relative to the control was 47.6%, 39.6%, 46.7%, 47.9%, and 48.8% for Punica, Betula, Ginkgo, Camellia, and Cudrania treatments, respectively. Ciliate populations were reduced by more than 60% in flavonoid-rich PE treatments. The Fibrobacter succinogenes diversity in all added flavonoid-rich PE was shown to increase, while the Ruminoccocus albus and R. flavefaciens populations in all PE decreased as compared with the control. In particular, the F. succinogenes community with the addition of Birch extract increased to a greater extent than that of others. In conclusion, the results of this study showed that flavonoid-rich PE decreased ruminal methane emission without adversely affecting ruminal fermentation characteristics in vitro in 24 h incubation time, suggesting that the flavonoid-rich PE have potential possibility as bio-active regulator for ruminants.

7.
Int J Hyperthermia ; 21(4): 319-32, 2005 Jun.
Article in English | MEDLINE | ID: mdl-16019858

ABSTRACT

The time course and extent of thermal ablative injury differs in liver compared to tumour tissue. This may be influenced by differences in the expression of heat shock proteins (HSP) and the response of Kupffer cells to thermal injury. This study determines the expression and response of HSP70 and Kupffer cells to thermal ablative injury in a Murine model of colorectal liver metastases. Thermal ablation by laser (Nd-YAG wavelength 1064 nm) was induced in liver and colorectal cancer liver metastases in CBA strain mice. Laser energy was applied at 2 W for 50 s and produced incomplete tumour ablation. Established tissue injury was assessed in separate groups of animals at time points ranging from 12 h to 21 days following therapy. HSP70 and Kupffer cell expression at the margins of coagulated tissue was determined by immunohistochemical staining for HSP70 and F4/80 antigens, respectively. HSP70 was faintly expressed in the cytoplasm of all tumour cells, with distinct clusters exhibiting intense cytoplasmic and nuclear HSP70 staining (130+/-19 cells mm-2). Comparatively, HSP70 expression was uncommon in untreated control liver specimens (2+/-2 cells mm-2, p<0.001). Thermal ablation increased expression of HSP70 at coagulated tissue margins. The peak response in tumours occurred at 2 days post-ablation and was significantly greater than the peak response in liver, occurring at 12 h (809+/-80 cells mm-2 vs. 454+/-52 cells mm-2, p<0.001). HSP70 expression remained significantly elevated for 7 days following therapy in tumour tissue, compared to 3 days in liver. Kupffer cell numbers in untreated control tumours were significantly lower than in untreated control livers (285+/-23 cells mm-2 vs. 451+/-30 cells mm-2, p<0.001). Following thermal ablation, there was an initial decrease in Kupffer cell numbers at the margin of coagulation with subsequent persistent increases thereafter. In liver tissue, the peak Kupffer cell response occurred at 5 days post-therapy and was significantly greater than the peak response in tumour tissue 3 days post-thermal ablation (1074+/-34 cells mm-2 vs. 860+/-53 cells mm-2, p=0.007). Thermal ablation produces a greater and more prolonged HSP70 response in colorectal liver metastases than in liver tissue. It also induces persistent increases in Kupffer cell activity in liver and tumour tissue.


Subject(s)
Colorectal Neoplasms/metabolism , HSP70 Heat-Shock Proteins/metabolism , Hyperthermia, Induced , Kupffer Cells/cytology , Liver Neoplasms/metabolism , Animals , Colorectal Neoplasms/pathology , Colorectal Neoplasms/secondary , Colorectal Neoplasms/therapy , Immunohistochemistry , Liver Neoplasms/pathology , Liver Neoplasms/secondary , Liver Neoplasms/therapy , Mice , Mice, Inbred CBA
8.
Eur J Clin Nutr ; 58(3): 481-7, 2004 Mar.
Article in English | MEDLINE | ID: mdl-14985687

ABSTRACT

OBJECTIVE: To investigate whether vitamin B(6) supplementation had a beneficial effect on lowering fasting plasma homocysteine concentrations in coronary artery disease (CAD) patients. DESIGN: A single-blind intervention study. SETTING: The study was performed at the Taichung Veterans General Hospital, the central part of Taiwan. SUBJECTS: A total of 50 subjects were identified by cardiac catheterization to have at least 70% stenosis of one major coronary artery. In all, 42 patients successfully completed this study. INTERVENTIONS: Patients were randomly assigned to one of five groups and treated with a daily dose of placebo (n=8), 5 mg vitamin B(6) (n=8), 10 mg vitamin B(6) (n=8), 50 mg vitamin B(6) (n=9), or 5 mg folic acid combined with 0.25 mg vitamin B(12) (n=9) for 12 weeks. MAIN OUTCOME MEASURES: Nutrient intakes were recorded by using 24-h diet recalls when patients returned to the cardiology clinic before the intervention (week 0) and at week 12. Vitamin B(6) status was assessed by direct measures (plasma pyridoxal 5'-phosphate) and indirect measures (erythrocyte alanine and aspartate aminotransaminase activity coefficient). Fasting plasma homocysteine, serum folic acid, and vitamin B(12) were measured. RESULTS: Fasting plasma homocysteine concentration did not respond to high or low doses of vitamin B(6) when compared with a placebo treatment after 12 weeks of supplementation. The mean fasting plasma homocysteine concentration, however, decreased significantly after 12 weeks of folic acid combined with vitamin B(12) supplementation (P=0.047). Further, within group, mean fasting plasma homocysteine concentration was nonsignificantly increased by 25.5, 16.2, and 18.3% in placebo, 10 mg/day and 50 mg/day vitamin B(6) supplemented groups, respectively; whereas folic acid combined with vitamin B(12) supplementation significantly reduced fasting plasma homocysteine concentration by 32% (P<0.001). CONCLUSIONS: Our results indicate that vitamin B(6) supplementation alone is less effective than folic acid combined with vitamin B(12) in lowering plasma homocysteine concentrations in CAD patients. SPONSORSHIP: This study was supported by the National Science Council, Taiwan, Republic of China (NSC-91-2320-B-040-023).


Subject(s)
Coronary Artery Disease/blood , Folic Acid/administration & dosage , Homocysteine/blood , Vitamin B 12/administration & dosage , Vitamin B 6/administration & dosage , Adult , Aged , Aged, 80 and over , Dose-Response Relationship, Drug , Female , Folic Acid/blood , Humans , Male , Mental Recall , Middle Aged , Single-Blind Method , Treatment Outcome , Vitamin B 12/blood , Vitamin B 6/blood
9.
Eur Neuropsychopharmacol ; 11(4): 295-9, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11532384

ABSTRACT

Because of the potential adverse events and teratogenesis of antipsychotic drugs, it is important to find a safe and effective treatment for pregnant women with severe mental illness. The membrane hypothesis of schizophrenia provides a rationale to treat symptoms of schizophrenia with omega-3 PUFAs. We report a 30-year-old married woman with chronic schizophrenia, who experienced an episode of acute exacerbation of psychotic symptoms during pregnancy. After entering into an open trial of omega-3 PUFAs monotherapy, she showed a dramatic improvement in both positive and negative symptoms of schizophrenia and a significant increase of omega-3 PUFA composition in erythrocyte membrane. There were no adverse effects in this treatment. Thus, omega-3 PUFAs could be both beneficial and therapeutic to pregnant schizophrenic women.


Subject(s)
Fatty Acids, Omega-3/therapeutic use , Pregnancy Complications/drug therapy , Pregnancy Complications/psychology , Schizophrenia/drug therapy , Adult , Female , Humans , Pregnancy
12.
Biochem J ; 348 Pt 2: 281-9, 2000 Jun 01.
Article in English | MEDLINE | ID: mdl-10816420

ABSTRACT

The transcription factor Sp1 was previously shown to undergo proteasome-dependent degradation when cells were glucose-starved and stimulated with the adenylate cyclase inducer, forskolin. However, the control of the Sp1 degradation process is largely unknown. Using in vitro and in vivo interaction studies, we show in the present study that Sp1 interacts with human Sug1 [hSug1, also known as p45 or thyroid-hormone-receptor interacting protein ('TRIP1')], an ATPase subunit of the 26 S proteasome and a putative transcriptional modulator. This interaction with Sp1 occurs through the C-terminus of hSug1, the region that contains the conserved ATPase domain in this protein. Both in vitro studies, in reconstituted degradation assays, and in vivo experiments, in which hSug1 is overexpressed in normal rat kidney cells, show that full-length hSug1 is able to stimulate the proteasome-dependent degradation of Sp1. However, hSug1 truncations that lack either the N- or C-terminal domain of hSug1 act as dominant negatives, inhibiting Sp1 degradation in vitro. Also, an ATPase mutant of hSug1, while still able to bind Sp1, acts as a dominant negative, blocking Sp1 degradation both in vitro and in vivo. These results demonstrate that hSug1 is involved in the degradation of Sp1 and that ATP hydrolysis by hSug1 is necessary for this process. Our findings indicate that hSug1 is an exchangeable proteasomal component that plays a critical regulatory role in the proteasome-dependent degradation of Sp1. However, hSug1 is not the factor limiting Sp1 degradation in the cells treated with glucosamine. This and other considerations suggest that hSug1 co-operation with other molecules is necessary to target Sp1 for proteasome degradation.


Subject(s)
Adaptor Proteins, Signal Transducing , Carrier Proteins/metabolism , Cysteine Endopeptidases/metabolism , Multienzyme Complexes/metabolism , Podophyllin/analogs & derivatives , Transcription Factors , ATPases Associated with Diverse Cellular Activities , Animals , Carrier Proteins/genetics , Cell Line , Cloning, Molecular , Escherichia coli , Glutathione Transferase/metabolism , Humans , Intracellular Signaling Peptides and Proteins , Kidney , Kinetics , LIM Domain Proteins , Podophyllin/metabolism , Podophyllotoxin/analogs & derivatives , Proteasome Endopeptidase Complex , Rats , Recombinant Fusion Proteins/metabolism , Sequence Deletion , Transfection
13.
Zhong Yao Cai ; 22(8): 385-7, 1999 Aug.
Article in Chinese | MEDLINE | ID: mdl-12571883

ABSTRACT

Effective compositions of Eucommla ulmoides foliage, sampled from the south side west section of the Qinling Mountain area, are analyzed qualiatively and quantitatively. It is shown that the foliage contains plenty of mineral elements, seventeen amino acids, proteins, sugars, alkaloids, flavonoids, aucubin, chlorogenic acid, pinoresinol diglucoside, coffeic acid juice and Jingniping glucoside. Based on the analysis and the main material of Eucommla ulmoides foliage, a healthy beverage functioning especially on resisting tire actions is formulated and produced. This work has provided a dependable new idea for further exploitation and utilization of the natural resources.


Subject(s)
Beverages , Eucommiaceae , Plants, Medicinal , Amino Acids/analysis , Chlorogenic Acid/analysis , Conservation of Natural Resources , Eucommiaceae/chemistry , Plant Leaves/chemistry , Plants, Medicinal/chemistry , Trace Elements/analysis
14.
Biochem Biophys Res Commun ; 241(3): 675-81, 1997 Dec 29.
Article in English | MEDLINE | ID: mdl-9434767

ABSTRACT

Two novel human genes encoding putative potassium channels, kH1 and kH2, were identified from a human fetal brain cDNA library. Sequence analysis showed that kH1 and kH2 are homologous to rat IK8 and rat K13, respectively. The kH1 encodes a polypeptide of 495 amino acids, which shares 88% and 95% identity to IK8 at the nucleotide and amino acid level, respectively. The kH2 encodes a polypeptide of 515 amino acids with 86% and 92% identity to K13 at the nucleotide and amino acid level, respectively. Northern blot studies revealed that one mRNA species, approximately 5kb, of the kH1 was expressed abundantly in tissues examined, including the heart, skeletal muscle, and less abundant in the brain, liver, kidney, and pancreas. Interestingly, an alternative spliced form of 2.4 kb mRNA species of the kH1 was also found in the brain. Unlike kH1, 2.4 kb of kH2 was expressed predominantly in the brain, placenta, and the skeletal muscle where it shared a differently spliced form of the kH2 mRNA, approximately 2.0 kb. Fluorescence in situ hybridization localized kH1 to the human chromosome 2p25 and kH2 to the human chromosome 20q13.


Subject(s)
Chromosome Mapping , Potassium Channels, Voltage-Gated , Potassium Channels/genetics , Potassium Channels/isolation & purification , Amino Acid Sequence , Animals , Base Sequence , Blotting, Northern , Brain , Chromosomes, Human, Pair 2 , Chromosomes, Human, Pair 20 , DNA, Complementary/isolation & purification , Fetus , Humans , Molecular Sequence Data , Open Reading Frames , Organ Specificity/genetics , Potassium Channels/chemistry , Rats
15.
Dig Dis Sci ; 38(2): 289-94, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8425441

ABSTRACT

Both cyclooxygenase products, such as prostaglandin (PG) E2, and lipoxygenase products, such as leukotriene (LT) B4, are increased in colitis and have potent proinflammatory actions. We studied effects of specific inhibitors of cyclooxygenase and 5-lipoxygenase on the healing of acetic acid colitis in rats. Acetic acid colitis was induced 24 hr before enzyme inhibition began. Four days after induction of colitis, the area of gross colonic mucosal damage was determined by image analysis. Eicosanoid content in the intestinal lumen was quantitated by radioimmunoassay following chromatographic purification. Under these conditions, indomethacin significantly retarded the healing of colonic lesions and inhibited PGE2 by > 90% compared to placebo-treated colitis rats. AA861 had no effect on the healing of lesions, although > 75% inhibition of leukotriene synthesis was demonstrated. These results suggest that inhibition of endogenous colonic prostaglandins can impair healing mechanisms in acute colitis even after inflammation has developed. In contrast, inhibition of leukotriene synthesis did not affect healing.


Subject(s)
Colitis/drug therapy , Cyclooxygenase Inhibitors/therapeutic use , Eicosanoids/metabolism , Lipoxygenase Inhibitors/therapeutic use , Wound Healing/drug effects , Acetates , Acetic Acid , Analysis of Variance , Animals , Benzoquinones/administration & dosage , Colitis/chemically induced , Colitis/metabolism , Colitis/pathology , Colon/drug effects , Colon/pathology , Disease Models, Animal , Drug Evaluation, Preclinical , Eicosanoids/analysis , Indomethacin/administration & dosage , Male , Rats , Rats, Sprague-Dawley
16.
Miner Electrolyte Metab ; 14(4): 229-34, 1988.
Article in English | MEDLINE | ID: mdl-2850461

ABSTRACT

The effect of calcitonin (CT) and the interaction of vitamin D and prostaglandin E2 with CT on renal tubular calcium reabsorption was examined in conscious, restrained thyroparathyroidectomized (TPTX) rats. Each rat was infused with a medium containing a fixed concentration of Ca (0-30 mM) to obtain steady-state serum and urinary Ca before CT administration. Constant infusion of CT (0.01-0.5 U/h) caused a dose-dependent reduction in serum and urinary Ca excretion within 2 h and reached another steady state. There were no significant changes in inulin clearance in any groups of animals before and after CT administration. By plotting urinary Ca excretion against-serum Ca, the effect of CT on tubular Ca reabsorption can be estimated. In vitamin D-replete rats, 0.05 U/h CT as well as 0.5 U/h CT caused a stimulation of tubular Ca reabsorption. In vitamin D-deficient rats, tubular reabsorptive capacity for Ca is much lower than that in vitamin D-replete rats. Furthermore, stimulation of tubular Ca reabsorption was observed only with a high dose (0.5 U/h) of CT. Simultaneous administration of 20 micrograms/h prostaglandin E2 (PGE2), that caused an inhibition of CT-induced stimulation of 1,25-dihydroxyvitamin D3, 1,25(OH)2D3, synthesis and phosphaturia [Endocrinology 116: 693-697, 1985], did not affect the effect of CT on the renal tubular Ca reabsorption. These results demonstrate that CT stimulates renal tubular Ca reabsorption, and that vitamin D status modulates the responsiveness of renal tubules to CT.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Calcitonin/pharmacology , Calcium/blood , Cholecalciferol/pharmacology , Dinoprostone/pharmacology , Kidney Tubules/metabolism , Parathyroid Glands/physiology , Thyroidectomy , Animals , Calcium/urine , Inulin/pharmacokinetics , Kidney Tubules/drug effects , Male , Rats , Rats, Inbred Strains , Reference Values , Vitamin D Deficiency/metabolism
17.
Pharmacol Biochem Behav ; 24(5): 1257-61, 1986 May.
Article in English | MEDLINE | ID: mdl-3487801

ABSTRACT

The inhibition of hindpaw (non-opiate) footshock-induced analgesia (HP-FSIA) by cimetidine, the histamine H2-receptor antagonist, was characterized in rats, and the drug's presence in brain was demonstrated. Cimetidine (100 mg/kg, IP) inhibited HP-FSIA when administered 30 min before testing, but was inactive when testing began sooner (15 min) or later (1-4 hr) than this time. Lower doses (20 mg/kg) were also ineffective when given 30 min before testing, whereas higher doses (200 mg/kg) effectively inhibited the response. Increasing the footshock current from 4 mA (which elicited cimetidine-sensitive analgesia) to higher currents (5 and 6 mA) yielded cimetidine-insensitive analgesia. Administration of isotopically labeled cimetidine (100 mg/kg, IP, 30 min) yielded whole brain cimetidine levels of 1.95 nmols/g, respectively, with a brain/blood ratio of 0.017. These findings confirm a limited penetration of brain by cimetidine, and show that large peripheral doses of cimetidine are required to block brain H2-receptors. The specific dose and time requirements for cimetidine to inhibit the HP-FSIA are probably attributable to the brain drug levels that can be achieved after peripheral administration.


Subject(s)
Brain/metabolism , Cimetidine/pharmacology , Electric Stimulation Therapy , Transcutaneous Electric Nerve Stimulation , Animals , Cimetidine/blood , Cimetidine/metabolism , Dose-Response Relationship, Drug , Injections, Intraperitoneal , Male , Rats , Rats, Inbred Strains
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