Isoflurane unveils a critical role of glutamate transporter type 3 in regulating hippocampal GluR1 trafficking and context-related learning and memory in mice

Glutamate transporter type 3 (EAAT3) may play a role in cognition. Isoflurane enhances EAAT3 trafficking to the plasma membrane. Thus, we used isoflurane to determine how EAAT3 might regulate learning and memory and the trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, such as GluR1, to the plasma membrane, a fundamental biochemical process for learning and memory. Here, isoflurane increased EAAT3 but did not change GluR1 levels in the plasma membrane of wild-type mouse hippocampus. Isoflurane increased protein phosphatase activity in the wild-type and EAAT3(-/-) mouse hippocampus. Also, isoflurane reduced GluR1 in the plasma membrane and decreased phospho-GluR1 in EAAT3(-/-) mice. The phosphatase inhibitor okadaic acid attenuated these effects. Finally, isoflurane inhibited context-related fear conditioning in EAAT3(-/-) mice but not in wild-type mice. Thus, isoflurane may increase GluR1 trafficking to the plasma membrane via EAAT3 and inhibit GluR1 trafficking via protein phosphatase. Lack of EAAT3 effects leads to decreased GluR1 trafficking and impaired cognition after isoflurane exposure in EAAT3(-/-) mice.

Cerebral vasodilator properties of Danshen and Gegen: a study of their combined efficacy and mechanisms of actions

Danshen and Gegen are two commonly used Chinese herbal medicines for treatment of cardiovascular diseases. The aim of the present study was to elucidate the combination effects of these two herbs on cerebral vascular tone and their underlying mechanisms of actions. Basilar artery rings were obtained from rats and precontracted with U46619. Cumulative administrations of aqueous extracts of Danshen, Gegen, or the two herbs combined (DG; ratio 7:3) produced concentration-dependent relaxation of the artery rings. Statistical analysis on these findings produced a combination index (CI) of 1.041 at ED50, which indicates the two herbs produced additive vasodilator effects when used as a combined decoction. Removal of the endothelium had no effect on the vasodilator properties of Danshen, Gegen, and DG. However, their maximum effects (Imax) were significantly blunted by a KATP channel inhibitor glibenclamide, a non-selective K(+) channel inhibitor tetraethylammonium (TEA), and by a combination of K(+) channel inhibitors (glibenclamide+TEA+iberiotoxin+4-aminopyridine+barium chloride). In addition, Danshen, Gegen, and DG produced augmentation of KATP currents and inhibited Ca(2+) influx in vascular smooth muscle cells isolated from rat basilar arteries. Furthermore, these agents inhibited CaCl2-induced contraction in the artery rings. In conclusion, the present study showed that Danshen and Gegen produced additive vasodilator effects on rat cerebral basilar arteries. These effects were independent of endothelium-derived relaxant factors (EDRF), but required the opening of KATP channels and inhibition of Ca(2+) influx in the vascular smooth muscle cells. It is suspected that the cerebral vasodilator effects of Danshen and Gegen produced either on their own or in combination, can help patients with obstructive cerebrovascular diseases.

Pyrrolidine dithiocarbamate attenuates surgery-induced neuroinflammation and cognitive dysfunction possibly via inhibition of nuclear factor κB

Surgery induces learning and memory impairment. Neuroinflammation may contribute to this impairment. Nuclear factor κB (NF-κB) is an important transcription factor to regulate the expression of inflammatory cytokines. We hypothesize that inhibition of NF-κB by pyrrolidine dithiocarbamate (PDTC) reduces neuroinflammation and the impairment of learning and memory. To test this hypothesis, four-month-old male Fischer 344 rats were subjected to right carotid exploration under propofol and buprenorphine anesthesia. Some rats received two doses of 50mg/kg PDTC given intraperitoneally 30min before and 6h after the surgery. Rats were tested in the Barnes maze and fear conditioning paradigm begun 6days after the surgery. Expression of various proteins related to inflammation was examined in the hippocampus at 24h or 21days after the surgery. Here, surgery, but not anesthesia alone, had a significant effect on prolonging the time needed to identify the target hole during the training sessions of the Barnes maze. Surgery also increased the time for identifying the target hole in the long-term memory test and decreased context-related learning and memory in fear conditioning test. Also, surgery increased nuclear expression of p65, a NF-κB component, decreased cytoplasmic amount of inhibitor of NF-κB, and increased the expression of interleukin-1β, interleukin-6, ionized calcium binding adaptor molecule 1 and active matrix metalloproteinase 9 (MMP-9). Finally, surgery enhanced IgG extravasation in the hippocampus. These surgical effects were attenuated by PDTC. These results suggest that surgery, but not propofol-based anesthesia, induces neuroinflammation and impairment of learning and memory. PDTC attenuates these effects possibly by inhibiting NF-κB activation and the downstream MMP-9 activity.

Identification of a novel HLA-B*27 allele, B*27:79 and the B*27 subtype polymorphism in the Hunan ethnic Han population of China

This article describes a novel HLA-B*27 allele, HLA-B*27:79, which was identified in a Hunan Han ethnic individual of China by a PCR sequence-based typing method. The new sequence has one nucleotide mutation at position 437(A→T) compared with the allele B*27:04:01. This nucleotide change causes an amino acid substitution from Aspartate (Asp) to Valine (Val) at codon 122. This is the first report of mutation at this position in the HLA-B locus. Then, we investigated the HLA-B*27 subtype polymorphism of the Hunan Han population, and the results showed that B*27:04, B*27:05 and B*27:06 are the predominant subtypes with the allele frequencies 0.97%, 0.26% and 0.10% respectively.

Optimization of culture of mesenchymal stem cells: a comparison of conventional plate and microcarrier cultures

OBJECTIVES

There has been increasing interest in mesenchymal stem cells (MSCs) because of their potential use for regenerative therapy; however, there is no well-defined protocol for MSCs culture. This study compares techniques of conventional plate and microcarrier culturing of MSCs.

METHODS AND RESULTS

Here, different conditions for isolation and expansion of rat MSCs have been examined and it was found that plating density and plating time in primary culture played important roles for culture of these rat MSCs. When plated at 10(8) /cm(2) density for 72 h, in primary culture, recycling stem cells (RS cells) predominated, and characteristics of rat MSCs (including morphology, growth rate, phenotype and differentiation potentials) remained stable during expansion until passage 14. For subculture of the cells, it was found that their growth rate when incubated at 33 °C was higher than those incubated at 37 °C, and maximal increase was 10- and 6-fold respectively. When cultured using microcarriers, at a density of 1 × 10(5) /mg beads, growth kinetics, phenotype and differentiation potentials also remained constant for cells between passage 2nd and 14th; their maximal number increased 16-fold.

CONCLUSIONS

Compared to conventional plate culture, culture using gelatine porous microcarrier Cultispher-S was superior for large-scale production of rat MSCs.

Cyclooxygenase-2 (COX-2) mediates arsenite inhibition of UVB-induced cellular apoptosis in mouse epidermal Cl41 cells

Inorganic arsenic is an environmental human carcinogen, and has been shown to act as a co-carcinogen with solar ultraviolet (UV) radiation in mouse skin tumor induction even at low concentrations. However, the precise mechanism of its co-carcinogenic action is largely unknown. Apoptosis plays an essential role as a protective mechanism against neoplastic development in the organism by eliminating genetically damaged cells. Thus, suppression of apoptosis is thought to contribute to carcinogenesis. It is known that cyclooxygenase-2 (COX-2) can promote carcinogenesis by inhibiting cell apoptosis under stress conditions; and our current studies investigated the potential contribution of COX-2 to the inhibitory effect of arsenite in UV-induced cell apoptosis in mouse epidermal Cl41 cells. We found that treatment of cells with low concentration (5 μM) arsenite attenuated cellular apoptosis upon UVB radiation accompanied with a coinductive effect on COX-2 expression and nuclear factor-κB (NFκB) transactivation. Our results also showed that the COX-2 induction by arsenite and UVB depended on an NFκB pathway because COX-2 co-induction could be attenuated in either p65-deficient or p50-deficient cells. Moreover, UVB-induced cell apoptosis could be dramatically reduced by the introduction of exogenous COX-2 expression, whereas the inhibitory effect of arsenite on UVB-induced cell apoptosis could be impaired in COX-2 knockdown C141 cells. Our results indicated that COX-2 mediated the anti-apoptotic effect of arsenite in UVB radiation through an NFκB-dependent pathway. Given the importance of apoptosis evasion during carcinogenesis, we anticipated that COX-2 induction might be at least partially responsible for the co-carcinogenic effect of arsenite on UVB-induced skin carcinogenesis.

Mechanisms of the cerebral vasodilator actions of isoflavonoids of Gegen on rat isolated basilar artery

ETHNOPHARMACOLOGICAL RELEVANCE

Gegen (root of Pueraria lobata) is used in traditional Chinese medicine for treatment of cardiovascular diseases. In this study, the relaxant actions of three of its isoflavonoids; puerarin, daidzein, and daidzin, were investigated on rat-isolated cerebral basilar artery.

MATERIALS AND METHODS

Rat basilar artery rings were precontracted with 100 nM U46619. Involvement of endothelium-dependent mechanisms was investigated by mechanical removal of the endothelium and inhibitors of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzymes. Adenylyl cyclase- and guanylyl cyclase-dependent pathways were investigated using their respective inhibitors 9-(tetrahydro-2-furanyl)-9H-purine-6-amine (SQ22536) and 1H-[1,2,4]oxadiazolo [4,3-[alpha]]-quinoxalin-1-one (ODQ). K(+) channels were investigated by pretreatment of the artery rings with various K(+) channel inhibitors, and Ca(2+) channels were investigated in artery rings incubated with Ca(2+)-free buffer and primed with 100 nM U46619 for 5 min prior to adding CaCl(2) to elicit contraction.

RESULTS

Puerarin, daidzein, and daidzin produced concentration-dependent relaxation of the artery rings with concentration that produced 50% inhibition (IC(50)) of 304 ± 49 μM, 20 ± 7 μM, and 140 ± 21 μM, respectively. Removal of the endothelium produced no change on their vasorelaxant responses except the maximum response (I(max)) to puerarin was inhibited by 28%. The NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME; 100 μM) also produced 45% inhibition on the puerarin-induced vasorelaxant response, but not the COX inhibitor flurbiprofen (10 μM). SQ22536 (100 μM) and ODQ (100μM) did not affect the vasodilator responses to puerarin, daidzein and daidzin, but glibenclamide (1μM), tetraethylammonium (TEA, 100mM) or a combination of K(+) channel inhibitors (100nM iberiotoxin+1mM 4-aminopyridine+100 μM barium chloride+1 μM glibenclamide+100mM TEA) reduced their I(max). The contractile response to CaCl(2) was attenuated by 61% and 34% in the presence of daidzein and daidzin, respectively, whereas, puerarin did not significantly affect the contraction.

CONCLUSIONS

The vasorelaxant action of daidzein and daidzin involved opening of K(+) channels and inhibition of Ca(2+) influx in the vascular smooth muscle cells. There is no evidence supporting involvement of endothelium-derived relaxing factors (EDRFs) in their actions. In contrast, puerarin produced vasodilatation via an endothelium-dependent mechanism involving nitric oxide production and an endothelium-independent pathway mediated by the opening of K(+) channels. The cerebral vasodilator activities of all these three isoflavonoids may be beneficial to patients with obstructive cerebrovascular diseases.

Isoflurane postconditioning induces neuroprotection via Akt activation and attenuation of increased mitochondrial membrane permeability

We have shown that isoflurane application at the onset of reperfusion (postconditioning) reduces brain ischemic injury in rats. This study was designed to determine whether this protection involved activation of prosurvival protein kinases and maintenance of normal mitochondrial membrane permeability. Two-month-old male rats were subjected to a 90-min middle cerebral arterial occlusion. They then were exposed or were not exposed to 2% isoflurane for 1 h. Ischemic penumbral cerebral cortex was harvested immediately and separated into the mitochondrial and cytosolic fractions. We showed that the mitochondrial nicotinamide adenine dinucleotide content in the ischemic penumbral cortex was significantly reduced, suggesting an increased mitochondrial membrane permeability. This increase was partly attenuated by isoflurane postconditioning. The mitochondrial adenosine diphosphate content in the penumbral cortex was reduced no matter whether the animals were postconditioned with isoflurane. The mitochondrial adenosine triphosphate concentration was not different among various experimental conditions. The phospho-Akt in the cytosolic and mitochondrial fractions of the ischemic penumbral cortex was higher than that in the control cortex. This increase trended to be higher in animals with isoflurane postconditioning. A similar change pattern was observed in the mitochondrial phospho-glycogen synthase kinase 3β, an Akt substrate that can regulate the mitochondrial membrane permeability. Isoflurane postconditioning reduced oxygen-glucose deprivation-induced injury of rat cortical neuronal cultures and increased phospho-Akt in these cells. The isoflurane postconditioning-induced protection in the neuronal cultures was decreased by the Akt inhibitor LY294002. These results suggest that isoflurane postconditioning effects may be mediated by Akt and involve reduced mitochondrial membrane permeability.

Glutamate transporter type 3 knockout mice have a decreased isoflurane requirement to induce loss of righting reflex

Excitatory amino acid transporters (EAAT) uptake extracellular glutamate, the major excitatory neurotransmitter in the brain. EAAT type 3 (EAAT3), the main neuronal EAAT, is expressed widely in the CNS. We have shown that the volatile anesthetic isoflurane increases EAAT3 activity and trafficking to the plasma membrane. Thus, we hypothesize that EAAT3 mediates isoflurane-induced anesthesia. To test this hypothesis, the potency of isoflurane to induce immobility and hypnosis, two major components of general anesthesia, was compared in the CD-1 wild-type mice and EAAT knockout mice that had a CD-1 strain gene background. Hypnosis was assessed by loss of righting reflex in this study. The expression of EAAT1 and EAAT2, two widely expressed EAATs in the CNS, in the cerebral cortex and spinal cord was not different between the EAAT3 knockout mice and wild-type mice. The concentration required for isoflurane to cause immobility to painful stimuli, a response involving primarily reflex loops in the spinal cord, was not changed by EAAT3 knockout. However, the EAAT3 knockout mice were more sensitive to isoflurane-induced hypnotic effects, which may be mediated by hypothalamic sleep neural circuits. Interestingly, the EAAT3 knockout mice did not have an altered sensitivity to the hypnotic effects caused by ketamine, an i.v. anesthetic that is a glutamate receptor antagonist and does not affect EAAT3 activity. These results suggest that EAAT3 modulates the sensitivity of neural circuits to isoflurane. These results, along with our previous findings which suggests that isoflurane increases EAAT3 activity, indicate that EAAT3 may regulate isoflurane-induced behavioral changes, including anesthesia.

Mechanisms of the relaxant effect of a danshen and gegen formulation on rat isolated cerebral basilar artery

AIM OF THE STUDY

Danshen (root of Salvia miltiorrhiza) and gegen (root of Pueraria lobata) are two herbs used in traditional Chinese medicine, most commonly for their putative cardioprotective and anti-atherosclerotic effects. In this study, the actions of a danshen and gegen formulation (DG; ratio 7:3) were investigated on rat-isolated cerebral basilar artery.

MATERIALS AND METHODS

Rat basilar artery rings were precontracted with 100 nM U46619. Involvement of endothelium-dependent mechanisms was investigated by mechanical removal of the endothelium; K(+) channels were investigated by pretreatment of the artery rings with various K(+) channel inhibitors, and Ca(2+) channels were investigated in artery rings incubated with Ca(2+)-free buffer and primed with 100 nM U46619 for 5 min prior to adding CaCl(2) to elicit contraction.

RESULTS

DG produced concentration-dependent relaxation of the artery rings with an IC(50) of 895±121 μg/ml. Mechanical removal of the endothelium or pretreatment with the BK(Ca) channel inhibitor iberiotoxin (100 nM), the K(V) channel inhibitor 4-aminopyridine (1 mM), or the K(IR) channel inhibitor barium chloride (100 μM), all had no effect on the DG-induced response (P>0.05 for all). However, pretreatment with the K(ATP) channel inhibitor glibenclamide (1 μM), the non-selective K(+) channel inhibitor tetraethylammonium (TEA, 100 mM), or a combination of all the K(+) channel inhibitors (iberiotoxin+4-aminopyrindine+barium chloride+glibenclamide+TEA) produced significant inhibition on the DG-induced response (P<0.01 for all); its maximum vasorelaxant effect (Imax) was reduced by 37, 24, and 30%, respectively. Preincubation of the artery rings with DG for 10 min produced concentration-dependent (1, 3 and 7 mg/ml) and total inhibition on the CaCl(2)-induced vasoconstriction.

CONCLUSIONS

These findings suggest the vasorelaxant effect of DG on rat basilar artery is independent of endothelium-derived mediators, whereas, inhibition of Ca(2+) influx in the vascular smooth muscle cells is important, and a minor component is mediated by the opening of K(ATP) channels. DG could be a useful cerebroprotective agent in some patients with occlusive cerebrovascular disease.

Ethyl acetate fraction of the root of Rubia cordifolia L. inhibits keratinocyte proliferation in vitro and promotes keratinocyte differentiation in vivo: potential application for psoriasis treatment

Psoriasis is a skin disease associated with hyperproliferation and aberrant differentiation of keratinocytes. Our previous studies have identified the root of Rubia cordifolia L. as a potent antiproliferative and apoptogenic agent in cultured HaCaT cells (IC(50) 1.4 microg/ml). In the present study, ethanolic extract of Radix Rubiae was fractioned sequentially with hexane, ethyl acetate (EA), n-butanol and water. EA fraction was found to possess most potent antiproliferative action on HaCaT cells (IC(50) 0.9 microg/ml). Mechanistic study revealed that EA fraction induced apoptosis on HaCaT cells, as it was capable of inducing apoptotic morphological changes. Annexin V-PI staining assay also demonstrated that EA fraction significantly augmented HaCaT apoptosis. In addition, EA fraction decreased mitochondrial membrane potential in a concentration- and time-dependent manner. The standardized EA fraction was formulated into topical gel and its keratinocyte-modulating action was tested on mouse tail model. EA fraction dose-dependently increased the number and thickness of granular layer and epidermal thickness on mouse tail skin, indicative of the keratinocyte differentiation-inducing activity. Taking the in vitro and in vivo findings together, the present preclinical study confirms that EA fraction is a promising antipsoriatic agent warranting further development for psoriasis treatment.

Morphine preconditioning reduces lipopolysaccharide and interferon-gamma-induced mouse microglial cell injury via delta 1 opioid receptor activation

Microglial cells play an important role in the inflammatory response of a broad range of brain diseases including stroke, brain infection and neurodegenerative diseases. However, there is very little information regarding how to protect microglial cells. Here, we showed that incubation of the C8-B4 mouse microglial cells with lipopolysaccharide (LPS) plus interferon-gamma (IFN gamma) induced cytotoxicity as assessed by the amount of lactate dehydrogenase (LDH) released from the cells. Preconditioning the cells with morphine for 30 min concentration-dependently reduced LPS plus IFN gamma-induced cell injury. This morphine preconditioning effect was abolished by naloxone, a general opioid receptor antagonist, by naltrindole, a selective delta opioid receptor antagonist and by 7-benzylidenenaltrexone maleate, a selective delta(1) opioid receptor antagonist. However, this protective effect was not affected by beta-funaltrexamine, a selective mu opioid receptor antagonist, nor-binaltorphimine, a selective kappa opioid receptor antagonist or naltriben, a selective delta(2) opioid receptor antagonist. LPS plus IFN gamma induced the expression of inducible nitric oxide synthase (iNOS), which was not affected by morphine preconditioning. Our results suggest that morphine induced a preconditioning effect in microglial cells. This effect may be mediated by delta 1 opioid receptors and may not be through inhibiting the expression of iNOS, a potentially harmful protein.

Isoflurane preconditioning improves short-term and long-term neurological outcome after focal brain ischemia in adult rats

Isoflurane preconditioning improved short-term neurological outcome after focal brain ischemia in adult rats. It is not known whether desflurane induces a delayed phase of preconditioning in the brain and whether isoflurane preconditioning-induced neuroprotection is long-lasting. Two months-old Sprague-Dawley male rats were exposed to or were not exposed to isoflurane or desflurane for 30 min and then subjected to a 90 min middle cerebral arterial occlusion (MCAO) at 24 h after the anesthetic exposure. Neurological outcome was evaluated at 24 h or 4 weeks after the MCAO. The density of the terminal deoxynucleotidyl transferase biotinylated UTP nick end labeling (TUNEL) positive cells in the penumbral cerebral cortex were assessed 4 weeks after the MCAO. Also, rats were pretreated with isoflurane or desflurane for 30 min. Their cerebral cortices were harvested for quantifying B-cell lymphoma-2 (Bcl-2) expression 24 h later. Here, we showed that pretreatment with 1.1% or 2.2% isoflurane, but not with 6% or 12% desflurane, increased Bcl-2 expression in the cerebral cortex, improved neurological functions and reduced infarct volumes evaluated at 24 h after the MCAO. Isoflurane preconditioning also improved neurological functions and reduced brain infarct volumes in rats evaluated 4 weeks after the MCAO. Isoflurane preconditioning also decreased the density of TUNEL-positive cells in the penumbral cerebral cortex. We conclude that isoflurane preconditioning improves short-term and long-term neurological outcome and reduces delayed cell death after transient focal brain ischemia in adult rats. Bcl-2 may be involved in the isoflurane preconditioning effect. Desflurane pretreatment did not induce a delayed phase of neuroprotection.

A nine-gene predictor of therapy response in adult Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL)

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Background: Ph+ ALL in adults shows a poor response to therapy and high frequency of relapse. This study utilized a meta-analysis of previous genome-wide gene expression studies to define and validate a nine-gene predictor of outcome in Ph+ ALL patients. Methods: Normalized gene expression data from previously published studies of 672 ALL patients were analyzed to identify genes associated with therapy response. Expression of the selected genes was assessed using Applied Biosystems low density reverse transcription quantitative PCR (RT-qPCR) arrays in bone marrow (BM) samples from 27 adult Ph+ ALL patients treated with standard chemotherapy plus a tyrosine kinase inhibitor. Therapy responses were defined at the molecular level by monitoring BCR/ABL1 levels, and categorized into 3 groups: optimal, persistent and relapse. Median follow up was 6 months (range 4–15). Median disease-free survival among the optimal and relapse groups were 12 and 5 months respectively (p = 0.002). There was no statistical difference in age, initial peripheral blood white cell and BM blast counts, and initial normalized BCR/ABL1 levels between groups. Differentially expressed genes were selected using the significance analysis of microarrays (SAM). Hierarchical clustering and principal component analysis were applied to assess the correlation between gene expression pattern and therapy response. A predictive model was built using support vector machines. Differences in survival among groups were compared by Kaplan-Meier analysis. Results: Data mining and pathway analysis of the published data identified 46 genes in 7 pathways potentially associated with therapy response (p < 0.001). RT-qPCR results from a 15 case training set, 5 in each outcome group, identified 9 genes that classified the cases with 100% accuracy. Validation using an additional 12 cases showed 91.7% prediction accuracy (ROC error = 0.056). Compared with the initial diagnostic samples, gene expression pattern in relapsed samples shifted to that resembling the persistent group. Conclusions: Using data-trimming of whole genome expression studies, we defined and validated a nine-gene signature that is an independent predictive marker for therapy response in adult Ph+ ALL patients.

No significant financial relationships to disclose.

Pharmacokinetic characterization of hydroxylpropyl-beta-cyclodextrin-included complex of cryptotanshinone, an investigational cardiovascular drug purified from Danshen (Salvia miltiorrhiza)

1. The study aimed to investigate the pharmacokinetics of cryptotanshinone in a hydroxylpropyl-beta-cyclodextrin-included complex in dogs and rats. 2. Animals were administrated the inclusion complex of cryptotanshinone and the concentrations of cryptotanshinone and its major metabolite tanshinone IIA were determined by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. 3. Cryptotanshinone in inclusion complex was absorbed slowly after an oral dose, and the C(max) and AUC(0-)(t) were dose-proportional. The bioavailability of cryptotanshinone in rats was (6.9% +/- 1.9%) at 60 mg kg(-1) and (11.1% +/- 1.8%) in dogs at 53.4 mg kg(-1). The t(1/2) of the compound in rats and dogs was 5.3-7.4 and 6.0-10.0 h, respectively. Cryptotanshinone showed a high accumulation in the intestine, lung and liver after oral administration, while the lung, liver and heart had the highest level following intravenous dose. Excretion data in rats showed that cryptotanshinone and its metabolites were mainly eliminated from faeces and bile, and the dose recovery rate was 0.02, 2.2, and 14.9% in urine, bile, and faeces, respectively. 4. The disposition of cryptotanshinone in an inclusion complex was dose-independent and the bioavailability was increased compared with that without cyclodextrin used to formulate the drug. Cryptotanshinone was distributed extensively into different organs. Excretion of cryptotanshinone and its metabolites into urine was extremely low, and they were mainly excreted into faeces and bile.

Preclinical factors affecting the pharmacokinetic behaviour of tanshinone IIA, an investigational new drug isolated from Salvia miltiorrhiza for the treatment of ischaemic heart diseases

Tanshinone IIA (TSIIA) is a major active triterpenoid isolated from Salvia miltiorrhiza. The purposes of this study were to investigate various preclinical factors that determined the pharmacokinetics of TSIIA. After oral dosing at 6.7, 20, and 60 mg kg(-1), TSIIA was detected mainly as glucuronidated conjugate (TSIIAG) with only small amounts of the unchanged in the plasma. TSIIA was predominantly excreted into the bile and faeces as TSIIAG, and urine to a minor extent. The C(max) and AUC(0-)(t) of TSIIAG after i.p. administration were significantly lower than those after intragastric administration. The plasma concentration-time profiles of TSIIA following oral dosing of TSIIA showed multiple peaks. The C(max) and AUC(0-)(t) of TSIIA and its glucuronides in rats with intact bile duct were significantly lower than those of rats with bile duct cannulation. Studies from the linked-rat model and intraduodenal injection of bile containing TSIIA and its metabolites indicate that TSIIA glucuronides underwent hydrolysis and the aglycone was reabsorbed from the gut and excreted into the bile as conjugates. TSIIA had a wide tissue distribution, with a very high accumulation in the lung, but very limited penetration into the brain and testes. TSIIA was metabolized by rat CYP2C, 3A and 2D, as ticlopidine, ketoconazole and quinidine all inhibited TSIIA metabolism in rat liver microsomes. Taken collectively, these findings indicate that multiple factors play important roles in determining the pharmacokinetics of TSIIA.