Metabolic abnormalities associated with ketamine-associated bladder toxicity based on metabolomics / 药学学报

The aim of the present study was to determine the metabolic changes and possible toxic mechanisms of ketamine-associated bladder toxicity. Twenty-four male Sprague-Dawley (SD) rats were randomly allocated into a control group, a low-dose group and a high-dose group. The behavior of these rats was observed every day. In addition, the weight, 2 h urinary frequency and organ coefficient of the bladder were measured. Serum IL-6 and TNF-α levels were measured using an enzyme-linked immunosorbent assay (ELISA). Urinary metabolites were analyzed using gas chromatography-mass spectrometry (GC-MS). This research was approved by the Ethics Committee of the Animal Experiment Center of Southwest Medical University (No. 201901-98). After 12 weeks of administration, the frequency of 2 h urination and the bladder mass index were significantly different in the low-dose and high-dose groups compared with the control group. Serum IL-6 and TNF-α levels were higher than those of the control group (P<0.05). Bladder HE staining showed that long-term administration of ketamine could induce cystitis. The concentrations of the three common differential metabolites, including 3-aminoisobutyric acid, citric acid and uric acid in the low-dose and the high-dose groups were increased compared with those in the control group. This study indicates that 3-aminoisobutyric acid, citric acid and uric acid and their related metabolic pathways may be closely related to ketamine-associated bladder toxicity.

Research advances on detecting heavy metals and harmful elements based on fluorescent probe quantum dots / 中草药

In recent years, it is a hot spot of research on detecting heavy metals such as Pb (II), Cu (II), and Hg (II) and harmful element As (III) based on novel fluorescence probe quantum dots (QDs). This review introduced the preponderance optical properties and advantages of QDs. In addition, the principles of fluorescence quenching concerning ion complexing reaction, electron transfer, fluorescence resonance energy transfer and others, fluorescence enhancement and methods combined with rolling circle amplification of DNA, redshift of emission wavelength, fluorescence ratio and others were presented. Finally, the paper summarized the applications and took prospect to provide the basis for the detections of heavy metals and harmful elements in Chinese materia medica based on fluorescence probes QDs.

Comparison of distribution of cholinergic nerves and M2 receptors between rat atria and ventricles / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the general pattern of cholinergic nerve distribution and M(2) receptors in adult rat heart.</p><p><b>METHODS</b>Karnovsky-Roots histochemical staining combining point counting method and immunochemical SABC method with image analysis were used to identify the cholinergic nerves and M(2) receptors, respectively, in adult rat heart.</p><p><b>RESULTS</b>Positive staining of cholinergic nerves and M(2) receptors was found in all regions of the rat heart, and the point count of cholinergic nerves in the atria was 4.6 times as much as that in ventricles, and the area of immunoreactive substance for M(2) receptors two-fold higher in the atria than in the ventricles. The point counts of the cholinergic nerves in the medial-layer myocardium were fewer than that in subepicardial and endocardial tissues of the left ventricular free wall. However, M(2) receptors were comparable among the 3 layers of the left free ventricular wall.</p><p><b>CONCLUSION</b>Cholinergic nerves and M(2) receptors are located in both rat atria and ventricles, but their density is much higher in the atria than in the ventricles. Transmural heterogeneity characterizes cholinergic nerve innervation in the left ventricular free wall without significant differences in M(2) receptor density.</p>

Voltage-activated potassium channel blockers inhibit anisodamine-induced relaxation of rabbit aortic smooth muscles precontracted with noradrenaline / 生理学报

Anisodamine, which is originally extracted from scopolia tangutica and is currently produced in China, is a tropane alkaloid and a muscarinic cholinoceptor blocker. Our previous study found that anisodamine did not alter high K(+)-evoked contraction of rabbit aortic rings using isometric tension recording methods, but could attenuate noradrenaline (NA)-, histamine- or 5-hydroxytryptamine-induced contraction in an endothelium-independent manner. Since the high K(+)-elicited depolarization non-selectively inhibits potassium channels in vascular smooth muscle cell (VSMC) membrane, the vasodilation effect of some potassium channel activators may be inhibited or abolished in high K(+) solution. We hypothesized that some potassium channels in VSMC membrane might play a role in the anisodamine-induced relaxation of blood vessels. The present experiment was designed to investigate whether potassium channel blockers inhibit anisodamine-induced relaxation of the rabbit isolated aortic rings. In a 8-min period, 1, 3 and 10 micromol/L of anisodamine, significantly relaxed the 0.01 micromol/L NA precontracted aortic ring by (19.1+/-3.1)%, (30.1+/-3.8)% and (38.3+/-4.2)%, respectively, compared with the controls [by (4.8+/-2.4)%, (5.1+/-1.8)% and (5.6+/-2.5)%, respectively] (P<0.01). 10 mmol/L of CsCl (a non-selective potassium channel blocker), 1 mmol/L of 4-aminopyridine [a selective voltage-activated potassium channel (K(V)) blocker], 10 mumol/L BaCl2 (a selective inwardly-rectifying potassium channel blocker), 10 micromol/L of glibenclamide (a selective ATP-sensitive potassium channel blocker), 3 micromol/L of charybdotoxin (a large- and intermediate-conductance Ca(2+)-activated potassium channels blocker) and 3 micromol/L of apamin (a selective small conductance Ca(2+)-activated potassium channel blocker) significantly increased the NA-induced contraction by (14.4+/-3.2)%, (16.3+/-5.8)%, (12.7+/-4.2)%, (13.6+/-2.0)%, (11.1+/-5.5)% and (13.4+/-4.3)%, respectively, compared with the control [by (5.6 +/-1.2)%] (P<0.01). In the presence of 10 and 30 mmol/L CsCl or 1 and 3 mmol/L 4-aminopyridine, anisodamine-induced relaxation of the 0.01 micromol/L NA contracted rabbit aortic rings [(28.8+/-3.0)% and (15.9+/-3.7)% or (29.7+/-3.9)% and (19.0+/-5.0)%] significantly deceased, compared with that in the absence of any potassium channel blocker [(38.3+/-4.2)% (P<0.01)] in a 8-min period. However, in the presence of 10, 30 micromol/L of BaCl2, 10, 30 micromol/L of glibenclamide, 3 micromol/L of charybdotoxin, or 3 micromol/L apamin, 10 micromol/L anisodamine-induced relaxation [(37.1+/-3.8)%, (36.2+/-4.7)%, (36.1+/-2.7)%, (35.6+/-3.3)%, (37.8+/-2.0)% and (39.3 +/-4.7) %, respectively] did not decrease, compared with the control [(38.3+/-4.2)%] (P>0.05). This study suggests that K(V) blockers inhibit anisodamine-induced relaxation of the rabbit aortic smooth muscle precontracted with NA and implies that the K(V) in VSMC membrane plays a role in anisodamine-induced relaxation of blood vessels.