Calycosin Influences the Metabolism of Five Probe Drugs in Rats.

BACKGROUND: Calycosin (CAL), a type of O-methylated isoflavone extracted from the herb Astralagusmembranaceus (AM), is a bioactive chemical with antioxidative, antiphlogistic and antineoplastic activities commonly used in traditional alternative Chinese medicine. AM has been shown to confer health benefits as an adjuvant in the treatment of a variety of diseases. AIM: The main objective of this study was to determine whether CAL influences the cytochrome P450 (CYP450) system involved in drug metabolism. METHODS: Midazolam, tolbutamide, omeprazole, metoprolol and phenacetin were selected as probe drugs. Rats were randomly divided into three groups, specifically, 5% Carboxymethyl cellulose (CMC) for 8 days (Control), 5% CMC for 7 days + CAL for 1 day (single CAL) and CAL for 8 days (conc CAL), and metabolism of the five probe drugs evaluated using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). RESULTS: No significant differences were observed for omeprazole and midazolam, compared to the control group. T max and t1/2 values of only one probe drug, phenacetin, in the conc CAL group were significantly different from those of the control group (T max h: 0.50±0.00 vs 0.23±0.15; control vs conc CAL). C max of tolbutamide was decreased about two-fold in the conc CAL treatment group (conc vs control: 219.48 vs 429.56, P<0.001). CONCLUSION: Calycosin inhibits the catalytic activities of CYP1A2, CYP2D6 and CYP2C9. Accordingly, we recommend caution, particularly when combining CAL as a modality therapy with drugs metabolized by CYP1A2, CYP2D6 and CYP2C9, to reduce the potential risks of drug accumulation or ineffective treatment.

Effects of salidroside on rat CYP enzymes by a cocktail of probe drugs.

OBJECTIVES: In this study, we aimed to evaluate the effect of salidroside on the activities of the different drug-metabolizing enzymes CYP1A2, CYP2B6, CYP2C9, CYP2D6 and CYP3A4 in rats, in which a specific probe drug was used for each enzyme. MATERIALS AND METHODS: After pretreatment with salidroside, five probe drugs were simultaneously administered to rats by gavage. The given dose was 2.0 mg/kg for phenacetin (CYP1A2 activity), 4.0 mg/kg for bupropion (CYP2B6 activity), 2.0 mg/kg for losartan (CYP2C9 activity), 8.0 mg/kg for metoprolol (CYP2D6 activity) and 1.0 mg/kg for midazolam (CYP3A4 activity). Then, an ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to analyze the concentrations of rats' blood, which were collected at different corresponding times. RESULTS: Our data showed that salidroside exhibited an inductive effect on CYP1A2, CYP2B6, CYP2C9 and CYP3A4 activities by changing the main pharmacokinetic parameters (t1/2, CL/F, Cmax and AUC(0-∞)) of the four probe drugs in rats. However, no significant changes in CYP2D6 activity were observed. CONCLUSION: In a word, the results displayed that salidroside could induce the activities of CYP1A2, CYP2B6, CYP2C9 and CYP3A4, which may influence the disposition of the drugs that are mainly metabolized by these pathways. Our research can provide the basis for the study of related herb-drug interactions in clinic.

Local cutaneous nerve terminal and mast cell responses to manual acupuncture in acupoint LI4 area of the rats.

Previous studies have shown that the effects of manual acupuncture (MA) are contributed by collagen fibers and mast cells in local acupoints, at which acupuncture stimulation causes various afferent fiber groups to be excited. However what happens in local nerve fibers and mast cells after MA remains unclear. The aim of this study was to examine the response of cutaneous nerve fibers and mast cells to MA stimulation in acupoint Hegu (LI4). The contralateral LI4 of the same rat was used as a non-stimulated control. Immnohistochemistry analysis were carried out to observe the expression of histamine (HA), serotonin (5-HT) and nociceptive neuropeptides, calcitonin gene-related peptide (CGRP) and substance P (SP), in the LI4 area. Mast cells were labeled with anti-mast cell tryptase antibody and simultaneously with HA or 5-HT primary antibodies to observe their co-expression. Our results showed that SP and CGRP were expressed more highly on the cutaneous nerve fibers of LI4 after MA stimulation than that of the control. Mast cells aggregated in close proximity to the blood vessels in intra-epidermis and dermis and some of them with degranulation in the lower dermis and subcutaneous tissue of LI4. Both mast cells and their granules appeared with HA (+) and 5-HT (+) expression at stimulated L14 sites, while a few intact mast cells with a little expression of 5-HT and HA were distributed in areas of non-stimulated L14. The results indicated that local cutaneous nerve terminals and mast cells responded to MA with higher expression of SP and CGRP in nerve fibers, as well as with aggregation and degranulation of mast cells with HA and 5-HT granules at acupoint LI4. These neuroactive substances may convey signals to certain pathways that contribute to the effects of acupuncture.

[Distribution of calcitonin gene related peptide positive neurofibers in local skin tissues of "Neiting"(ST 44), "Zusanli" (ST 36) and "Futu" (ST 32) regions in the rat]. / é™é’™ç´ åŸºå› ç›¸å ³è‚½é˜³æ€§è¡¨è¾¾ç¥žç»çº¤ç»´åœ¨å¤§é¼ "å† åº­""足三里""ä¼å ”"穴区皮肤组织中的分布

OBJECTIVE: To observe the distribution of calcitonin gene related peptide (CGRP)-positive neurofibers in local tissues of "Neiting"(ST 44), "Zusanli" (ST 36) and "Futu" (ST 32) regions in the hind limbs of rats. METHODS: Five adult male SD rats were used in the present study. The local skin tissues of acupoint "Neiting" (ST 44), "Zusanli" (ST 36) and "Futu" (ST 32) regions were dissected from the rat that underwent transcardiac perfusion with 4% paraformaldehyde, and cut into sections (20 microm in thickness), followed by staining with CGRP fluorescent immunohistochemical method and with phalloidin and DAPI, respectively. After that, CGRP-positive neurofibers of the samples were observed and recorded using a laser confocal microscope. RESULTS: CGRP-positive nerve fibers were found to distribute in the dermis and subcutaneous layers of local tissues of acupoint ST 44, ST 36 and ST 32, mainly concentrating around the vessel-like structure. The number and length of CGRP-positive nerve fibers were most in the ST 44 region, more in the ST 36 region and fewer in the ST 32 region, in turn (P<0.01). The distribution of the vessel-like structure also presented a decreasing trend in the above-mentioned three acupoint regions in turn. CONCLUSION: CGRP-positive neurofibers are an important element in the local tissues of acupoint ST 44, ST 36 and ST 32 regions, and present a decreasing tendency in the number from the distal to the proximal part of the hind-limb, showing a similar tendency of needling sensation in the human body in which a more hypersensitivity exists in the distal part of the limb.

Manual acupuncture and laser acupuncture for autonomic regulations in rats: observation on heart rate variability and gastric motility.

This study focused on the effects of laser acupuncture (LA) and manual acupuncture (MA) at different acupoints on gastric motility and heart rate variability (HRV) simultaneously to elucidate the site specific effects of acupoints and the correlation between changes of gastric motility and low frequency/high frequency (LF/HF) ratio. Gastric motility and HRV were recorded before and during MA or LA. Stimulating PC-6 or ST-36 significantly enhanced gastric motility, while BL-21 caused no changes. In contrast, MA or LA at CV-12 significantly suppressed gastric motility. Stimulating PC-6 or ST-36 significantly increased heart rate (HR), while CV-12 or BL-21 induced no significant changes of HR. Stimulating PC-6 significantly increased LF/HF, while ST-36, CV-12, or BL-21 induced no significant effects. These results indicated that there was acupoint specificity in the effects of acupuncture on gastric motility and HRV. The stimulatory effect of MA and LA at PC-6 and ST-36 on HR was associated with sympathetic activity. The stimulatory effect of MA or LA at PC-6 or ST-36 on gastric motility was associated with vagal activity. Laser needle can be used as an alternative stimulation therapy.