Erratum to: Synthesis and Anticancer Activity of Functionalized Thieno[2,3-d]pyrimidine Compounds and Their Triazinyl and Tetrazinyl Derivatives

Russian Journal of Bioorganic Chemistry - erratum     

Effect of NO Synthase Inhibition on Cardiovascular Circadian Rhythms in Wild‐Type and eNOS‐Knock‐Out Mice

Cardiovascular functions (blood pressure [BP], heart rate [HR]) were radiotelemetrically studied in endothelial nitric oxide synthase (NOS) knock‐out mice (eNOS‐/‐) and their wild type C57BL/6 (WT) controls. Studies were performed with and without inhibition of the NOS with the non‐specific inhibitor N^ω‐Nitro‐L‐Arginin‐Methylester (L‐NAME). Six eNOS‐/‐and five WT mice, kept under a light:dark schedule of 12:12 h (lights on 07:00 h), were treated with L‐NAME in tap water containing different concentrations (94, 282, and 940 mg/kg) each for three days. Under control conditions, the eNOS‐/‐mice are mildly hypertensive in comparison to WT. L‐NAME increased systolic [SBP] and diastolic [DBP] blood pressures in WT mice to the levels of eNOS‐/‐mice after two days of L‐NAME application with no dose‐dependency, whereas L‐NAME had no effects on SBP and DBP in eNOS‐/‐mice. In neither mouse strain were the circadian rhythms in BP and HR affected by drug treatment. The similarity of the 24 h BP profiles in eNOS‐/‐and L‐NAME‐treated WT mice support the notion that only the enothelial NOS and not other NOS isoenzymes are of importance for hypertension in the knock‐out mouse strain.     

Prophylactic effect of aqueous propolis extract against acute experimental hepatotoxicity in vivo

Propolis has been extensively used in folk medicine for the management of a wide spectrum of disorders. In a previous study, we demonstrated the protective effect of the aqueous propolis extract (APE) against the injurious effects of carbon tetrachloride (CCl4) on hepatocytes in vitro. The present investigation was carried out to show whether the hepatoprotective effect of the extract could also be manifested in vivo. Rats were given APE orally for 14 consecutive days, before being subjected to a single intraperitoneal injection of CCl4. One day after the CCl4 injection, the animals were sacrificed, hepatocytes were isolated and liver homogenates were prepared for the assessment of liver injury. In isolated hepatocytes, APE afforded protection against CCl4-induced injury as manifested by a decrease in the leakage of the cytosolic enzyme lactate dehydrogenase (LDH), decreased generation of lipid peroxide and maintenance of cellular reduced glutathione (GSH) content. In principle, similar findings were observed in liver homogenates. The present findings show that APE has in vivo hepatoprotective potential which could be attributed at least in part to the maintenance of cellular GSH content. The latter effect seems to play an important role in conserving the integrity of biomembranes as it was associated with a decrease in lipid peroxidation and reduced leakage of cytosolic LDH.     

Putative cocaine receptor in striatum is a glycoprotein with active thiol function

Dopamine transporters of bovine and rat striata were identified by their specific [3H]cocaine binding and cocaine-sensitive [3H]dopamine [( 3H]DA) uptake. Both binding and uptake functions of bovine striatal transporters were potentiated by lectins. Concanavalin A (Con A) increased the velocity but did not change the affinity of the transporter for DA; however, it increased its affinity for cocaine without changing the number of binding sites. This suggests that the DA transporter is a glycoprotein and that Con A action on it produces conformational changes. Inorganic and organic mercury reagents inhibited both [3H]DA uptake and [3H]cocaine binding, though they were all more potent inhibitors of the former. n-Ethylmaleimide inhibited [3H]DA uptake totally but [3H]cocaine binding only partially. Also, n-pyrene maleimide had differential effects on uptake and binding, inhibiting uptake and potentiating binding. [3H]DA uptake was not affected by mercaptoethanol up to 100 mM, whereas [3H]cocaine binding was inhibited by concentrations above 10 mM. On the other hand, both uptake and binding were fairly sensitive to dimercaprol (less than 1 mM). The effects of all these sulfhydryl reagents suggest that the DA transporter has one or more thiol group(s) important for both binding and uptake activities. The Ellman reagent and dithiopyridine were effective inhibitors of uptake and binding only at fairly high concentration (greater than 10 mM). Loss of activity after treatment with the dithio reagents may be a result of reduction of a disulfide bond, which may affect the transporter conformation.     

Effect of NO synthase inhibition on cardiovascular circadian rhythms in wild-type and eNOS-knock-out mice

Cardiovascular functions (blood pressure [BP], heart rate [HR]) were radiotelemetrically studied in endothelial nitric oxide synthase (NOS) knock-out mice (eNOS-/-) and their wild type C57BL/6 (WT) controls. Studies were performed with and without inhibition of the NOS with the non-specific inhibitor N(omega)-Nitro-L-Arginin-Methylester (L-NAME). Six eNOS-/-and five WT mice, kept under a light:dark schedule of 12:12 h (lights on 07:00 h), were treated with L-NAME in tap water containing different concentrations (94, 282, and 940 mg/kg) each for three days. Under control conditions, the eNOS-/-mice are mildly hypertensive in comparison to WT. L-NAME increased systolic [SBP] and diastolic [DBP] blood pressures in WT mice to the levels of eNOS-/-mice after two days of L-NAME application with no dose-dependency, whereas L-NAME had no effects on SBP and DBP in eNOS-/-mice. In neither mouse strain were the circadian rhythms in BP and HR affected by drug treatment. The similarity of the 24 h BP profiles in eNOS-/-and L-NAME-treated WT mice support the notion that only the enothelial NOS and not other NOS isoenzymes are of importance for hypertension in the knock-out mouse strain.     

Experimental studies on the afferent innervation of the cricothyroid muscle in dogs

The cricothyroid muscle in dogs received branches from two independent nerves, namely the external ramus of the cranial laryngeal nerve and the pharyngeal branch of the vagus. Classical spindles are infrequent in the muscle. Atypical forms of sensory endings were identified. Two end-plates were frequently met with on a single extrafusal fibre. Sectioning of the external ramus of the cranial laryngeal nerve was followed by degeneration of spindles. Intact axons detected up to 6 months after operation are probably derived from the pharyngeal branch of the vagus. Chromatolytic changes occurred in the ipsilateral dorsal vagal nucleus and the capsulated ganglion at the entry of the nerve into the muscle. Chromatolysis occurred in the intramuscular ganglion cell rows and in neurons of the ipsilateral nodose ganglion. Morphological alterations were more pronounced in the ipsilateral medial column of the nucleus ambiguus. No changes were observed in the somata of the mesencephalic nucleus.     

Blockade of Nitric Oxide Overproduction and Oxidative Stress by <Emphasis Type="Italic">Nigella sativa</Emphasis> Oil Attenuates Morphine-Induced Tolerance and Dependence in Mice

The effects of Nigella sativa oil on morphine-induced tolerance and dependence in mice and possible mechanism(s) of these effects were investigated, for the first time, in this study. Repeated administration of Nigella sativa oil (4 ml/kg, p.o.) along with morphine (5 mg/kg, s.c.) attenuated the development of tolerance, as measured by the hot plate test, and dependence, as assessed by naloxone (5 mg/kg, i.p.)-precipitated withdrawal manifestations. Concomitantly, nitric oxide overproduction and increase in brain malondialdehyde level induced by repeated administration of morphine to mice or by administration of naloxone to morphine-dependent mice were inhibited by co-administration of the oil. Also, the decrease in brain intracellular reduced glutathione level and glutathione peroxidase activity induced by both treatments were inhibited by co-administration of the oil. The increase in brain glutamate level induced by both treatments was not inhibited by concurrent administration of the oil. The inhibitory effect of the oil on morphine-induced tolerance and dependence and on naloxone-induced biochemical alterations in morphine-dependent mice was enhanced by concurrent i.p. administration of the NMDA receptor antagonist, dizocilpine (0.25 mg/kg). Similarly, concurrent i.p. administration of the NO synthase inhibitors; L-N (G)-nitroarginine methyl ester (10 mg/kg), aminoguanidine (20 mg/kg) and 7-nitroindazole (25 mg/kg) or the antioxidant, N-acetylcysteine (50 mg/kg) enhanced this inhibitory effect of the oil. On the other hand, this effect was antagonized by concurrent i.p. administration of the nitric oxide precursor, L-arginine (300 mg/kg). These results provide evidence that Nigella sativa oil, through inhibition of morphine-induced NO overproduction and oxidative stress, appears to have a therapeutic potential in opioid tolerance and dependence.     

NMR-based metabolomic analysis of wild,greenhouse, and in vitro regenerated shoots of <Emphasis Type="Italic">Cymbopogon schoenanthus</Emphasis> subsp. <Emphasis Type="Italic">proximus</Emphasis> with GC–MS assessment of proximadiol

Cymbopogon schoenanthus subsp. proximus is a wild plant distributed in subtropical and east Africa extending from the north to the southern parts of Egypt. Widely used in folk medicine, it is the source of the diuretic sesquiterpene proximadiol. Nuclear magnetic resonance metabolomic analysis of polar extracts of shoots from wild, greenhouse, somatic embryos, and direct and indirect organogenic in vitro cultures was carried out. Metabolic profiling yielded 39 compounds, of which common metabolites were 15 (38.4%). Unique metabolites were trehalose (2.5%) in the wild plants, 2-hydroxylisobutyrate, galactarate and tyrosine (7.6%) in indirect organogenic shoots. Tartrate was found only in direct regenerated shoots (2.5%). Metabolites identified in greenhouse and embryogenic shoots showed no unique compounds. Multivariate analysis revealed significant differences between all tested shoots. 4-aminobutyrate, alanine, glutamine, glucose, fructose, and sucrose were the most significantly different metabolites. Proximadiol was identified and quantitatively measured from the non-polar extract of different types of shoots using gas chromatography and mass spectrometry (GC–MS). Concentrations ranged from 3.6 ± 0.03 to 198.6 ± 7.2 µg/100 mg dry weight in regenerated shoots from somatic embryogenesis and in wild plant shoots, respectively. Direct organogenesis yielded the highest in vitro concentration (20.3 ± 0.5 µg/100 mg dry weight). This study reported the metabolic profiling of C. schoenanthus polar extract and identified primary metabolites that are unique to the wild type and shoots regenerated from different in vitro cultures. Proximadiol was quantified and the in vitro culture system yielding the highest concentration relative to the wild plant was identified.