Hexobarbital Sleep Test for Predicting the Susceptibility or Resistance to Experimental Posttraumatic Stress Disorder

Hexobarbital sleep test (HST) was performed in male Wistar rats (hexobarbital 60 mg/kg, i.p.) 30 days prior to stress exposure. Based on the duration of hexobarbital-induced sleep, rats were divided into two groups, animals with high intensity (fast metabolizers (FM), sleep duration <15 min) or low intensity of hexobarbital metabolism (slow metabolizers (SM), sleep duration ≥15 min). The SM and FM groups were then divided into two subgroups: unstressed and stressed groups. The stressed subgroups were exposed to predator scent stress for 10 days followed by 15 days of rest. SM and FM rats from the unstressed group exhibited different behavioral and endocrinological patterns. SM showed greater anxiety and higher corticosterone levels. In stressed animals, anxiety-like posttraumatic stress disorder (PTSD) behavior was aggravated only in SM. Corticosterone levels in the stressed FM, PTSD-resistant rats, were lower than in unstressed SM. Thus, HST was able to predict the susceptibility or resistance to experimental PTSD, which was consistent with the changes in glucocorticoid metabolism.

Lactic acid bacteria and natural antimicrobials to improve the safety and shelf-life of minimally processed sliced apples and lamb's lettuce

Outbreaks of food-borne disease associated with the consumption of fresh and minimally processed fruits and vegetables have increased dramatically over the last few years. Traditional chemical sanitizers are unable to completely eradicate or kill the microorganisms on fresh produce. These conditions have stimulated research to alternative methods for increasing food safety. The use of protective cultures, particularly lactic acid bacteria (LAB), has been proposed for minimally processed products. However, the application of bioprotective cultures has been limited at the industrial level. From this perspective, the main aims of this study were to select LAB from minimally processed fruits and vegetables to be used as biocontrol agents and then to evaluate the effects of the selected strains, alone or in combination with natural antimicrobials (2-(E)-hexenal/hexanal, 2-(E)-hexenal/citral for apples and thyme for lamb's lettuce), on the shelf-life and safety characteristics of minimally processed apples and lamb's lettuce. The results indicated that applying the Lactobacillus plantarum strains CIT3 and V7B3 to apples and lettuce, respectively, increased both the safety and shelf-life. Moreover, combining the selected strains with natural antimicrobials produced a further increase in the shelf-life of these products without detrimental effects on the organoleptic qualities.

Hepatoprotective and antioxidant activity of Leucas aspera against D-galactosamine induced liver damage in rats

CONTEXT

Whole plant of Leucas aspera (LA) Willd. (Labiatae) is traditionally used in Siddha medicine for hepatic ailments.

OBJECTIVE

LA was investigated for its hepatoprotective, antioxidant, and protective effect on microsomal drug metabolizing enzymes (MDMEs).

MATERIALS AND METHODS

LA aqueous extract (200 and 400 mg/kg, p.o.) was evaluated for its hepatoprotective and antioxidant activity in d-galactosamine (D-GalN)-induced hepatotoxicity in rats. Biochemical and histopathological studies were performed to assess hepatoprotective activity. Hexobarbitone-induced sleeping time model was used to study the protective effect of LA on MDMEs.

RESULTS

D-GalN administration induced hepatotoxicity in rats which was manifested by increased levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total cholesterol, triglycerides, total bilirubin and oxidative stress. Pretreatment with LA extract significantly protected the liver in D-GalN administered rats. LA extract significantly elevated antioxidant enzymes like superoxide dismutase, catalase, glutathione peroxidase and decreased lipid peroxidation levels in liver. The total phenolic and flavonoid content in LA aqueous extract was found to be 28.33 ± 0.19 gallic acid equivalents mg/g of extract and 3.96 ± 0.57 rutin equivalent mg/g of extract, respectively. LA extract (200 and 400 mg/Kg) treatment with CCl₄ decreased the hexobarbitone-induced sleeping time in mice by 56.67 and 71.30%, respectively, which indicated the protective effect of LA on hepatic MDMEs. Histological studies showed that LA at 400 mg/kg attenuated the hepatocellular necrosis in D-GalN intoxicated rats.

CONCLUSION

Our results contribute towards validation of the traditional use of LA in hepatic disorders.

[Effect of a new triazinoindole derivative on the functional state of CNS in animals under normoxia and hypoxia conditions]

The influence of the new triazinoindole derivative encoded VM-606 on the individual behavior of rats in the open-field and elevated-plus-maze tests has been studied under normal conditions and after exposure to hypoxia with hypercapnia. It is established that VM-606 at a dose of 50 mg/kg under normoxia conditions reduces emotional anxiety, orientation-investigation activity, and mobility factor, while under hypoxic conditions this drug reduces the severity of behavioral changes in test animals. The experiments on mice showed that the compound studied potentiates the hypnotic effect of hexenal. It is suggested that VM-606 exhibits psychosedative and stress-protector properties, which play a certain role in its antihypoxic effect.

Anticonvulsant, anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata Fresen

AIM OF THE STUDY

The objective of this study is to investigate the anticonvulsant, anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata.

MATERIALS AND METHODS

The anticonvulsant effect of the aqueous root extract (100, 200 and 400 mg/kg) was evaluated in mice using the strychnine- and picrotoxin-induced seizure models. Its anxiolytic activity was evaluated using the elevated plus maze (EPM) and the Y maze (YM) methods (Hogg, 1996; Yemitan and Adeyemi, 2003) while the hexobarbitone induced sleep and the hole board models were used to evaluate the sedative and exploratory activities in mice respectively. The acute toxicity studies and phytochemical analysis of the extract were also carried out.

RESULTS

The extract (100-400 mg/kg) produced a significant (P<0.01) dose dependent increase in onset of convulsion compared to the control for strychnine- and picrotoxin-induced seizures. It also produced a significant (P<0.01) dose dependent prolongation of the cumulative time spent in the open arms of the elevated plus maze and Y maze compared with the control. The extract (100-400 mg/kg) produced significant (P<0.01) reduction in the time of onset of sleep induced by hexobarbitone. The prolongation of hexobarbitone sleeping time by the extract (200 mg/kg) was comparable to that produced by diazepam (3 mg/kg). At doses of 100-400 mg/kg, the extract produced a dose dependent decrease in exploratory activity of the mice. The reduction in exploratory activity produced by the extract (400 mg/kg) was greater than that of chlorpromazine (1 mg/kg). The results obtained from the experiments indicate that the extract has central nervous system depressant and anxiolytic activities. The LD(50) obtained for the acute toxicity studies using both oral and intraperitoneal routes of administration were 1.74 g/kg and 19.95 mg/kg respectively.

CONCLUSION

These findings justify the use of Securidaca longepedunculata in traditional medicine for the management of convulsion and psychosis.

Hepatoprotective potential of aqueous extract of Butea monosperma against CCl(4) induced damage in rats

Aqueous extract of flowers of Butea monosperma (Fabaceae) was evaluated at different dose levels (200, 400, 800 mg/kg, p.o.) for its protective efficacy against CCl(4) (1.5 ml/kg i.p.) induced acute liver injury to validate its use in traditional medicines. The CCl(4) administration altered various biochemical parameters, including serum transaminases, protein, albumin, hepatic lipid peroxidation, reduced glutathione and total protein levels, which were restored towards control by therapy of B. monosperma Adenosine triphosphatase and glucose-6-phosphatase activity in the liver were decreased significantly in CCl(4) treated animals. Therapy of B. monosperma showed its protective effect on biochemical and histopathological alterations at all the three doses in dose dependent manner. B. monosperma extract possess modulatory effect on drug metabolizing enzymes as it significantly decreased the hexobarbitone induced sleep time and increased excretory capacity of liver which was measured by BSP retention. Histological studies also supported the biochemical finding and maximum improvement in the histoarchitecture was seen at higher dose of BM extract.

[Morpho-functional changes in the frog urinary bladder receptors under the influence of barbiturates]

The effect of hexenal and nembutal on the tissue bushy receptors was studied the living isolated frog urinary bladder using methylene blue staining. These drugs were shown to induce the changes in the receptor pulse activity which included three phases: an initial sharp increase, an abrupt decline and a low protracted plateau. Reactions to hexenal and nembutal, while possessing some common features, had their own peculiarities. Synchronously, the dynamics of methylene blue staining of the receptor elements was registered for the control of the intensity of oxidation-reduction processes in the receptor neuroplasm, that is for redox-system dynamics. It was found that the phases of this dynamics coincided in many respects with the phases of the receptor electric activity changes. No ultrastructural changes associated with the putative damaging effect of barbiturates on the receptors were recorded (during the exposure of 1-30 min). The most significant characteristic was an accumulation glycogen granules in the neuroplasm of the receptor elements, suggesting the prevalence of energy substrate deposition over its expenditure. Depression of the receptor pulse activity supports the assumption that barbiturates, besides their soporific and narcotic actions, apparently possess some anesthetic property.

Effects of crop development on the emission of volatiles in leaves of Lycopersicon esculentum and its inhibitory activity to Botrytis cinerea and Fusarium oxysporum

Volatiles emitted from the leaves of Lycopersicon esculentum at the two-, ten-leaf and anthesis periods were collected by a gas absorbing method and analyzed by gas chromatography (GC)-mass spectrometry. In total, 33 compounds of volatiles emitted from three developmental stage plants were separated and identified, and quantitatively analyzed by the internal standard addition method. All of the samples of volatile were found to be rich in monoterpenes and sesquiterpenes. beta-phellandrene and caryophyllene predominated in the volatiles of the leaves of plants at the two- and ten-leaf stages. Furthermore, (E)-2-hexenal were the dominant components in the volatiles emitted from anthesis plants. The results of volatiles analyzed show that the compositions varied depending on the developmental stages. The volatiles emitted from crushed tomato leaves of plants at the anthesis stage had the most strongly inhibitory activity against the spore germination and hyphal growth of Botrytis cinerea and Fusarium oxysporum, followed by ten- and two-leaf plants. However, the activity of volatiles, emitted from the leaves of plants at the two-leaf stage, in inhibiting F. oxysporum was greater than B. cinerea.

Antifungal activity of strawberry fruit volatile compounds against Colletotrichum acutatum

Eight volatile products characterizing strawberry aroma, which is generated from the oxidative degradation of linoleic and linolenic acids by a lipoxygenase (LOX) pathway, were examined because of their antifungal activity against Colletotrichum acutatum, one of the causal agents of strawberry anthracnose. In this study, the effects of aldehydes, alcohols, and esters on mycelial growth and conidia development were evaluated. (E)-Hex-2-enal was found to be the best inhibitor of mycelial growth [MID (minimum inhibitory doses)=33.65 microL L(-1)] and of spore germination (MID=6.76 microL L(-1)), while hexyl acetate was the least effective of all volatile compounds tested (MID=6441.89 microL L(-1) for mycelial growth and MID=1351.35 microL L(-1) for spore germination). Furthermore, the antifungal activity of (E)-hex-2-enal on susceptibility of strawberry fruits to C. acutatum was also confirmed. The presence of these molecules in jars containing strawberry fruits inoculated with a suspension of spores inhibited the fungus growth and prevented the appearance of symptoms. Moreover, a study of the effects of (E)-hex-2-enal on conidial cells of C. acutatum was evaluated by transmission electron microscopy. This volatile compound altered the structures of the cell wall and plasma membrane, causing disorganization and lysis of organelles and, eventually, cell death.

Propolis protects CYP 2E1 enzymatic activity and oxidative stress induced by carbon tetrachloride

Induction of CYP 2E1 by carbon tetrachloride (CCl(4)) is one of the central pathways by which CCl(4) generates oxidative stress in hepatocytes. Experimental liver injury was induced in rats by CCl(4) to determine toxicological actions on CYP 2E1 by microsomal drug metabolizing enzymes. In this report, ethanolic extract of propolis at a dose of 200 mg/kg (po) was used after 24 h of toxicant administration to validate its protective potential. Intraperitoneal injection of CCl(4) (1.5 ml/kg) induced hepatotoxicity after 24 h of its administration that was associated with elevated malonyldialdehyde (index of lipid peroxidation), lactate dehydrogenase and gamma-glutamyl transpeptidase release (index of a cytotoxic effect). Hepatic microsomal drug metabolizing enzymes of CYP 2E1 showed sharp depletion as assessed by estimating aniline hydroxylase and amidopyrine N-demethylase activity after CCl(4) exposure. Toxic effect of CCl(4) was evident on CYP 2E1 activity by increased hexobarbitone induced sleep time and bromosulphalein retention. Propolis extract showed significant improvement in the activity of both enzymes and suppressed toxicant induced increase in sleep time and bromosulphalein retention. Choleretic activity of liver did not show any sign of toxicity after propolis treatment at a dose of 200 mg/kg (id). Histopathological evaluation of the liver revealed that propolis reduced the incidence of liver lesions including hepatocyte swelling and lymphocytic infiltrations induced by CCl(4). Electron microscopic observations also showed improvement in ultrastructure of liver and substantiated recovery in biochemical parameters. Protective activity of propolis at 200 mg/kg dose was statistically compared with positive control silymarin (50 mg/kg, po), a known hepatoprotective drug seems to be better in preventing hepatic CYP 2E1 activity deviated by CCl(4). These results lead us to speculate that propolis may play hepatoprotective role via improved CYP 2E1 activity and reduced oxidative stress in living system.

Effect of Perinatal Low Protein Diets on the Ontogeny of Select Hepatic Cytochrome P450 Enzymes and Cytochrome P450 Reductase in the Rat

In the present study, we administered two low protein diets (LPDs) to rats during pregnancy and lactation and determined their effect on the ontogeny of select hepatic cytochrome P450 (P450) isoforms in their offspring. The L93 and LM76 LPDs were derived from the American Society of Nutrition recommended AIN93G and a modified version of the AIN76A purified control diets, respectively. The LPDs contained 8% crude protein in the form of casein, whereas the purified control diets contained 19% casein. A regular cereal-based diet (NP) was also included, and, therefore, a total of five groups were tested. Pups in all five groups were weaned onto a regular NP diet on postnatal day 28. Perinatal LPD altered the activities of a number of P450 isoforms in 28-day-old male and female offspring. However, nutritional rehabilitation abolished most of these changes as evidenced by lack of differences between the five groups in the activities of P450 isoforms in either 65- or 150-day-old offspring. Interestingly, 58-day-old female offspring in the LM76 group but not those in the L93 group exhibited shorter hexobarbital sleep time than the purified control group. However, hexobarbital hydroxylase activity and the amount of CYP2C12 protein, an important P450 isoform involved in hexobarbital metabolism in females, were unchanged. This suggests that the decrease in hexobarbital sleep time in this group is not due to an increase in the activity of hexobarbital-metabolizing enzymes. In summary, perinatal LPDs produced transient alterations in activities of select hepatic P450s and resulted in a gender- and diet-dependent long-term alteration in hexobarbital pharmacodynamics.

Anxiolytic activity of a novel potent serotonin 5-HT2C receptor antagonist FR260010: A comparison with diazepam and buspirone

Hyperfunction of brain 5-hydroxytryptamine(2C) (5-HT(2C)) receptor is suggested to be involved in anxiety as evidenced by the fact that a putative 5-HT(2C) receptor agonist 1-(m-chlorophenyl)-piperazine (m-CPP) causes anxiety in humans. We have recently identified FR260010 (N-[3-(4-methyl-1H-imidazol-1-yl)phenyl]-5,6-dihydrobenzo[h]quinazolin-4-amine dimethanesulfonate) as novel 5-HT(2C) receptor antagonist from diaryl amine derivatives, and here characterized in vitro and in vivo profiles of the compound. FR260010 showed high affinity for human 5-HT(2C) receptor (K(i): 1.10 nM) and high selectivity over 5-hydroxytryptamine(2A) (5-HT(2A)) receptor (K(i): 386 nM) and many other transmitter receptors. FR260010 showed antagonist activity at human 5-HT(2C) receptor in an intracellular calcium assay and showed no detectable intrinsic activity. The compound dose-dependently inhibited the hypolocomotion (ID(50): 1.89 mg/kg, p.o.) and hypophagia (ID(50): 2.84 mg/kg, p.o.) in rats induced by m-CPP, putative indices of brain 5-HT(2C) receptor antagonist activity. We then compared the effects of FR260010 with those of two other anxiolytics belonging to different classes, diazepam and buspirone, in anxiety models in rats and mice and adverse effect tests in mice. FR260010 (0.1-3.2 mg/kg, p.o.) and diazepam (1-10 mg/kg, p.o.) decreased behavioral indices of anxiety in all models, whereas buspirone (0.32-10 mg/kg, p.o.) did not significantly affect them in any models. In adverse effect tests, FR260010 and buspirone showed modest effects, whereas diazepam showed significant effects in all tests. These results suggest that FR260010 is a novel, potent, orally active and brain penetrable antagonist of 5-HT(2C) receptor, and may have therapeutic potential for treatment of anxiety, with more desirable profiles than benzodiazepines or 5-hydroxytryptamine(1A) (5-HT(1A)) receptor agonists.

Isolation, structure elucidation andIn Vivohepatoprotective potential oftrans-tetracos-15-enoic acid fromIndigofera tinctoriaLinn

The bioassay guided fractionation of the dried aerial part of Indigofera tinctoria Linn. led to the identification of an active fraction labelled as indigotin. On further chemical analysis, a compound isolated from indigotin was identified and characterized as trans-tetracos-15-enoic acid (TCA). The chemical structure of this compound was established on the basis of physical properties and spectral data, including NMR. It afforded significant hepatoprotection against carbon tetrachloride and paracetamol induced hepatotoxicity in experimental models. Silymarin, a well known plant based hepatoprotective agent, and N-acetylcysteine, which has proven efficacy as a replenisher of sulfhydryls, were used for relative efficacy. TCA was found to reverse the altered hepatic parameters in experimental liver damage. In the safety evaluation study the oral LD50 was found to be more than 2000 mg/kg, with no signs of abnormalities or any mortality for the 15 day period of observation after administration of a single dose of drug in mice. The studies revealed significant and concentration dependent hepatoprotective potential of TCA as it reversed the majority of the altered hepatic parameters in experimental liver damage in rats and mice and may be useful in the management of liver disorders.

Short and simple syntheses of 4-oxo-(E)-2-hexenal and homologs: pheromone components and defensive compounds of Hemiptera

One-step syntheses of 4-oxo-(E)-2-hexenal and 4-oxo-(E)-2-octenal from commercially available 2-ethyl- and 2-butylfuran are described. A two-step synthesis of the homolog 4-oxo-(E)-2-decenal from furan is also reported. These compounds are common components of true bug defensive secretions, and recently have been identified as pheromone components for several species. The simple syntheses reported here will make these compounds readily available for further research.

Variations in CYP74B2 (hydroperoxide lyase) gene expression differentially affect hexenal signaling in the Columbia and Landsberg erecta ecotypes of Arabidopsis

The CYP74B2 gene in Arabidopsis (Arabidopsis thaliana) ecotype Columbia (Col) contains a 10-nucleotide deletion in its first exon that causes it to code for a truncated protein not containing the P450 signature typical of other CYP74B subfamily members. Compared to CYP74B2 transcripts in the Landsberg erecta (Ler) ecotype that code for full-length hydroperoxide lyase (HPL) protein, CYP74B2 transcripts in the Col ecotype accumulate at substantially reduced levels. Consistent with the nonfunctional HPL open reading frame in the Col ecotype, in vitro HPL activity analyses using either linoleic acid hydroperoxide or linolenic acid hydroperoxide as substrates show undetectable HPL activity in the Col ecotype and C6 volatile analyses using leaf homogenates show substantially reduced amounts of hexanal and no detectable trans-2-hexenal generated in the Col ecotype. P450-specific microarrays and full-genome oligoarrays have been used to identify the range of other transcripts expressed at different levels in these two ecotypes potentially as a result of these variations in HPL activity. Among the transcripts expressed at significantly lower levels in Col leaves are those coding for enzymes involved in the synthesis of C6 volatiles (LOX2, LOX3), jasmonates (OPR3, AOC), and aliphatic glucosinolates (CYP83A1, CYP79F1, AOP3). Two of the three transcripts coding for aliphatic glucosinolates (CYP83A1, AOP3) are also expressed at significantly lower levels in Col flowers.

Attraction of Male European Tarnished Plant Bug, Lygus rugulipennis to Components of the Female Sex Pheromone in the Field

Previous work showed that females of the European tarnished plant bug, Lygus rugulipennis Poppius (Heteroptera: Miridae), produced three chemicals, hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal, and that these were suspected to be components of the female sex pheromone. In field experiments, traps baited with blends of these chemicals dispensed from polyethylene vials and sachets failed to catch significant numbers of males. Here, we report more recent field experiments in which the chemicals were released from glass microcapillary tubes. A blend of hexyl butyrate and (E)-4-oxo-2-hexenal was significantly attractive to male L. rugulipennis. In addition, whereas the mixture of all three components attracted fewer L. rugulipennis males, this tertiary blend captured significantly greater numbers of males of the congeneric species Lygus pratensis than the binary mixture. The possible reasons for the success of the microcapillaries compared with other dispensers are discussed.

General pharmacology of KP-102 (GHRP-2), a potent growth hormone-releasing peptide

The general pharmacological effects of the hexapeptide KP-102 (D-alanyl-3-(2-naphthyl)-D-alanyl-L-alanyl-L-tryptophyl-D-phenylalanyl-L-lysinamide dihydrochloride, growth hormone-releasing peptide-2, GHRP-2, pralmorelin, CAS 158861-67-7), which potently promotes growth hormone (GH) release by acting at both hypothalamic and pituitary sites, were evaluated in various animal experimental models. The administration of KP-102 showed no obvious effect at a pharmacological dose on the central nervous system. KP-102 had no significant effect on the autonomic nervous system and smooth muscle except a slight and transient increase in spontaneous motility of isolated rabbit ileum and contraction of isolated guinea pig ileum at high doses. There was negligible effect on the respiratory and cardiovascular systems, digestive system, renal function and blood system after KP-102 treatment. These results suggest that KP-102 has no serious general pharmacological effects at dose levels showing GH-releasing activity in the experimental animals. Therefore, it is concluded that KP-102 will be a useful drug for the diagnosis of serious GH deficiency and for treatment of short stature.

[Repellent effect of volatile oil from whitefly (Syngonium podophyllum) on aphids and its chemical constituents]

The interference effect of volatile oil from whitefly (Syngonium podophyllum) on aptera aphid, guard aphid (Aphis gossypii), mustard aphid (Lipaphis erysimi) and red peach aphid (Myzus persicae) was studied by using four arms olfraetometes. The results showed that the volatile oil had distinct repelling effect. The staying periods of test aphids in test areas were obviously shorter than in control areas, and the selecting frequencies were less than the control, too. The volatile oil did not show repelling effect on red peach aphid at the test concentrations. The components of the volatile oil from S. podophyllum were analysed by GC-MS. 43 constituents were identified.

Safety pharmacology of CKD-602, a novel anticancer agent

CKD-602 ((20S)-7-[2-(N-isopropylamino)-ethyl]-camptothecin.HCl, CAS 213819-48-8) is a new class of anticancer drug that belongs to the topoisomerase inhibitors. Its effect on the central nervous system (CNS), general behavior, cardiovascular-respiratory system and the other organ systems were studied. When intravenously administered, CKD-602 up to doses of 5 mg/kg caused an increase of body temperature, increase of respiration rate, decrease of gastrointestinal transport, showed analgesic action and produced antisecretory action in pylorus ligated rats. However, CKD-602 showed no effects on general behavior, motor coordination, spontaneous locomotor activity, hexobarbital sleeping time, convulsion, cardiovascular, smooth muscle and urinary tract system. These findings demonstrate that CKD-602 in doses up to 5 mg/kg has minor effects on the CNS in animals. However, CKD-602 does not exert any general pharmacological effects at the dose of 1 mg/kg except the effects on gastric secretion.

[Screening method for compounds acting at super low concentrations]

At present, there are no simple and reliable methods for selection of compounds with physiological activity in super-low concentrations (SLC). The screening system with high predictability is proposed. At the beginning, experiment is carried out on infusorians--spirostoma. Their motion activity, behavior, living ability and shape are registered at concentrations of substances in a range of 10(-3)-10(-13) mol/l. If the effect is detected on spirostoma, then experiments are performed on laboratory animals or their isolated tissues. Specific deviations on injection substance in SLC are detected, depending on compounds class. Nine representatives of different classes of biologically active compounds are investigated in the work: carbofos, deltametrin, 3-quinuclidinyl benzylate, atropine, phenosan, fenazepam, dopamine receptor antagonist SCH-23390, ciprine, and hexenal. It is accepted that if compound action in SLC is observed on spirostoma, then effects in super-low doses are also detected in a whole animal.

Synthesis and pharmacological activity of new carbonyl derivatives of 1-aryl-2-iminoimidazolidine: part 2. Synthesis and pharmacological activity of 1,6-diaryl-5,7(1H)dioxo-2,3-dihydroimidazo[1,2-a][1,3,5]triazines

Synthesis and pharmacological activity of 1,6-diaryl-5,7(1H)dioxo-2,3-dihydroimidazo-[1,2-a][1,3,5]triazines (C) are presented. The title compounds were obtained from 1-arylimidazolinurea derivatives in cyclization reaction with difunctional carbonyl reagents--phosgene (method I) or carbonyldiimidazole (CDI) (method II). Their molecular structures were confirmed by the X-ray analysis of 1-phenyl-6-(4-chlorophenyl)-5,7(1H)-dioxo-2,3-dihydroimidazo[1,2-a][1,3,5]triazine (C2) crystals. Compounds C exhibited significant depressive action on the central nervous system (CNS) of the laboratory animals, correlated with very low acute toxicity (LD(50) > 2000 mg kg(-1) i.p.), and showed antinociceptive activity in behavioural models. Reversion of this effect by small dose of naloxone (5 mg kg(-1)) can suggest opioid-like mechanism of antinociception produced by these and other carbonyl derivatives of 1-aryl-2-iminoimidazolidine. Additionally, an effect on the serotonin neurotransmission pathway was also observed. The receptor mechanism of activity for investigated compounds was confirmed only for the opioid mu receptor in binding affinity assay test. Same tests performed for the serotonin 5-HT(2) and benzodiazepine BZD receptors showed no affinity for tested compounds. The opioid-like and serotonergic activities are similar to these described earlier for chain carbonyl 1-aryl-2-iminoimidazolidine derivatives containing urea moiety, mainly due to similar chemical structure, although compounds C are not able to adopt any of the higher energy conformations of urea derivatives. Rigid location of aromatic ring (Ar') at N6, acting as a spacer blocking any direct access to the carbonyl groups (e.g. through the hydrogen bonding), could be responsible for lack of affinity toward 5-HT(2) expressed in the binding assay test.

Evaluation of toxic activity of 2,4-dihydroxythiobenzanilides

2,4-Dihydroxythiobenzanilides represent a new group of compounds with significant fungistatic and bacteriostatic properties. The results of investigations on their cytotoxicity are also very convincing. Therefore LD50 doses were determined for five compounds, they ranged from 239 to 840.5 mg/kg. The results of the tests for spontaneous locomotor activity and hexabarbiturane sleeping time indicate low toxicity of the compounds tested.

[Modulation by ultralow intensity electromagnetic fields on pharmacologic effects of psychotropic drugs]

The ultralow-intensity electromagnetic fields (EMF, frequency of 4200, modulated by a quasistochastic signal in the range of 20-20,000 Hz, power density of 15 microW/cm2, specific body absorption rate up to 4.5 mJ/kg) potentiated the hypnogenic effect of hexenal. The exposure to the EMF shortened the time of falling asleep induced by this drug and increased sleep duration in rats. The exposure to the EMF also potentiated haloperidol catalepsy: it decreased the drug threshold dose and increased the catalepsy duration. The EMF influence on the haloperidol effects was of a prolonged character: it was manifest in a selected suppression of the emotional excitation in the open-field test within 24 hours after the exposure.

[The effect of gamma-L-glutamylhistamine analogues on the severity of experimental anaphylactic reaction, hormonal status and liver cytochrome P450 system]

The influence of gamma-L-glutamylhistamine analogues on the hexenal-induced sleeping, glucocorticoid hormone content in blood plasma and severity of experimental anaphylactic reaction was studied. It was observed that gamma-L-glutamylhistamine analogues caused decrease in the sleeping time and severity of experimental anaphylactic reaction, the elevation of glucocorticoids content in blood plasma. The present results indicate that substances have the wide spectrum of biological activity which depends on the length of the N-acyl radical.

Interactions of melatonin with the liver microsomal cytochrome P450 system of rats and humans in vitro and effects on the P450 system and the antioxidative status in rat liver after acute treatment

In vitro melatonin binds to human and rat liver microsomal cytochrome P-450 (P450) according to a type II substrate. The affinity is similar to that of aniline with a general left-shift. Melatonin interferes with model monooxygenase reactions indicative of different P450 forms in humans and rats (in humans according to the lower specific P450 content less pronounced): the strongest inhibition was found for ethoxyresorufin O-deethylation, indicating the binding to P450 1A, the binding to P450 2B (ethoxycoumarin O-deethylation) was less pronounced, the least inhibition was found for P450 3A (ethylmorphine N-demethylation) reaction. The oxidase function was also inhibited: luminol amplified chemiluminescence was more inhibited than the lucigenin amplified one, hydrogen peroxide formation was inhibited at concentrations higher than 10(-4) M, microsomal NADPH/Fe stimulated lipid peroxidation was inhibited at concentrations higher than 10(5) M. In vivo melatonin prolonged hexobarbital sleeping time in rats in a dose dependent manner (ip. co-administration of 1, 5 and 20 mg/kg b.w. melatonin with 100 mg/kg hexobarbital). Immediately after awakening the animals were sacrificed: a small increase in P450 concentrations cannot be explained, no changes in P450 monooxygenase or oxidase activities nor in microsomal lipid peroxidation or GSH status could be observed.

Changes in rat liver monooxygenase activities after administration of atenolol, nifedipine and diltiazem alone and in combination

The effects of the Ca2+ antagonists nifedipine (NF) and diltiazem (DL) and of the cardioselective beta 1-adrenergic blocking agent atenolol (AT) on the hexobarbital (HB) sleeping time and on the activity of some liver drug-metabolizing enzyme systems in male Wistar rats were studied. Two hours after single oral administration, atenolol (150 mg/kg) did not change hexobarbital sleeping time, while nifedipine (50 mg/kg) and diltiazem (30 mg/kg) prolonged it by 171.2 and 99.6%, respectively. Coadministration of atenolol with diltiazem or with nifedipine significantly prolonged hexobarbital sleep by 205 and 283%, respectively. Administered alone, atenolol decreased the ethylmorphine-N-demethylase (EMND) activity, but the amidopyrine-N-demethylase (APND) activity was not changed in any of the treated groups. Atenolol and nifedipine significantly increased aniline-4-hydroxylase (AH) activity and this effect was also observed with the combinations AT + NF and AT + DL. The NADPH cytochrome P-450 reductase activity was significantly decreased by nifedipine and diltiazem. Only nifedipine increased the total content of cytochrome P-450 (by 23.8%). Atenolol and diltiazem tended to increase the content of cytochrome b5 which was increased by nifedipine by 97.6%. The same effect was observed with the combinations AT + NF and AT + DL. The results suggest that NF, AT + NF and AT + DL produced the manifested changes in hepatic oxidative metabolism. The decreased EMND activity by atenolol, however, and the prolongation of hexobarbital sleeping time by nifedipine, diltiazem and their coadministration with atenolol did not correlate with enhanced microsomal P-450 and b5 content.

Effects of volatile aldehydes from Aspergillus-resistant varieties of corn on Aspergillus parasiticus growth and aflatoxin biosynthesis

The fungi Aspergillus flavus and Aspergillus parasiticus produce a potent class of hepatocarcinogens known as aflatoxins. Corn-derived volatile compounds have been previously found to affect growth and aflatoxin production in A. flavus. In this study, the effects on A. parasiticus of three corn-derived volatile compounds, n-decyl aldehyde, hexanal and octanal, were measured. These three compounds were previously found to be variably expressed in five Aspergillus-resistant maize strains and three susceptible strains. In this study, A. parasiticus radial growth was restricted least by n-decyl aldehyde and most by octanal. Treatments of 100 microl of both hexanal and octanal were found to completely inhibit radial growth of the fungus using an agar plate assay method. While the volatile compound n-decyl aldehyde had less of an effect on radial growth than the other volatiles, the n-decyl aldehyde treated colonies had a predominance of uniquely aerial hyphae. These colony structures were found to have more complex hyphae and significantly fewer conidiophores than the control and other aldehyde treatments. Furthermore, aflatoxin production by the fungus was reduced by n-decyl aldehyde and hexanal, but was stimulated by octanal. The results presented here indicate that all three volatile compounds reduce radial growth but only n-decyl aldehyde significantly inhibits aflatoxin biosynthesis in A. parasiticus.

Does dihydrohonokiol, a potent anxiolytic compound, result in the development of benzodiazepine-like side effects?

The aims of this study were to assess whether dihydrohonokiol, 3'-(2-propenyl)-5-propyl-(1,1'-biphenyl)-2,4'-diol (DHH-B), a potent anxiolytic compound, developed benzodiazepine-like side effects. A 1 mg kg(-1) dose of diazepam, almost equivalent to the minimum dose for the anxiolytic effect, disrupted the traction performance, potentiated hexobarbital-induced sleeping and impaired learning and memory performance. DHH-B, even at a dose of 1 mg kg(-1) (i.e. five times higher than the minimum dose for significant anxiolytic effect) neither developed diazepam-like side effects nor enhanced the side effects of diazepam. Rather, the potentiation by diazepam of hexobarbital-induced sleeping was reduced by 1 mg kg(-1) DHH-B. Furthermore, mice treated with 10 daily administrations of 1 and 5 mg kg(-1) diazepam, but not 0.2-5 mg kg(-1) DHH-B, showed precipitated withdrawal symptoms characterized by hyper-reactivity, tremor and tail-flick reaction when they were challenged with flumazenil (10 mg kg(-1) i.p.). These results suggest that, unlike the benzodiazepine anxiolytic diazepam, DHH-B is less likely to induce motor dysfunction, central depression, amnesia or physical dependence at the effective dose required for the anxiolytic effect.

Influence of new monoterpene homologues of GABA on the central nervous system activity in mice

This behavioral study in mice showed that the monoterpene homologues of GABA (SL-1, SL-2 and SL-3), characterized by low toxicity, induced an increase in spontaneous locomotor activity (SL-2 and SL-3). Moreover, SL-3 shortened hexobarbital-induced sleeping time, and SL-1 showed anticonvulsant activity in pentetrazole-induced seizures.

Anaesthetic effects of pregnanolone in combination with allopregnanolone, thiopental, hexobarbital and flurazepam: an EEG study in the rat

The anaesthetic interactions of the steroid, 3 alpha-hydroxy-5 beta-pregnan-20-one, in male rats were investigated in different fixed binary combinations with the steroid allopregnanolone (3 alpha-hydroxy-5 alpha-pregnan-20-one), two barbiturates (thiopental and hexobarbital) and the benzodiazepine, flurazepam. Anaesthetic effects were determined using an EEG threshold method. Interactions were assessed using an isobolographic method. The interaction between the two steroids, pregnanolone and allopregnanolone, showed an anaesthetic effect significantly less than additive (antagonistic). The interactions between pregnanolone and the two barbiturates and the benzodiazepine showed an anaesthetic effect significantly greater than additive (potentiation) in all tests performed. These results could be explained by a pharmacodynamic interaction at the hypothetical GABA-benzodiazepine-barbiturate-steroid complex in the CNS.

Combined effect of propranolol with nifedipine or with diltiazem on rat liver monooxygenase activities

The effects of two Ca2+ antagonists nifedipine (NF) and diltiazem (DL) and of the nonselective beta-adrenergic blocking agent propranolol (PR) on the hexobarbital (HB) sleeping time and on the activity of some liver drug-metabolizing enzyme systems in male Wistar rats were studied. Two h after single oral administration PR (50 mg/kg) did not change HB sleeping time, while NF (50 mg/kg) and DL (30 mg/kg) prolonged it by 171.2 and 99.6%, respectively. Coadmistration of PR with DL or with NF significantly prolonged HB sleep by 240.7 and 129%, respectively. Only NF increased aniline 4-hidroxylase (AH) activity (by 92%) and the total P-450 content (by 24%). PR and NF increased cytochrome b5 content and this effect was also observed with the combinations PR + NF (by 109%) and PR + DL (by 102%). The NADPH cytochrome P-450 reductase activity was significantly decreased by NF and DL and after their combination with PR. The ethymorphine-N-demethylase (EMND) and amidopyrine-N-demethylase (APND) activities were not changed. The effects of PR, NF and DL administrated alone or in combination on liver oxidative metabolism are considered as possible mechanisms of drug interactions.

Honokiol, a putative anxiolytic agent extracted from magnolia bark, has no diazepam-like side-effects in mice

Use of the elevated plus-maze experiment and activity and traction tests in mice have revealed that seven daily treatments with 0.2 mg kg(-1) and higher doses of honokiol, a neolignane derivative extracted from Magnolia bark, had an anxiolytic effect without change in motor activity or muscle tone. Diazepam, 1 mg kg(-1), had the same anxiolytic potential as 0.2 mg kg(-1) honokiol but induced muscle relaxation. The aim of this study was to determine whether honokiol had diazepam-like side-effects. Mice treated with 1-10 mg kg(-1) diazepam, but not those treated with 0.1-2 mg kg(-1) honokiol, for 12 days showed withdrawal symptoms characterized by hyperactivity and running-fit when they were challenge-administered intraperitoneal flumazenil (10 mg kg(-1)) 24 h after the last treatment with diazepam. Oral diazepam (0.5-2 mg kg(-1), 10 min before) dose-dependently prolonged hexobarbital (100 mg kg(-1), i.p.)-induced sleeping, disrupted learning and memory, and inhibited (+)-bicuculline (40 mg kg(-1), i.p.)-induced death. Honokiol (0.2-20 mg kg(-1), p.o., 3 h before) had no such effects. The prolongation by diazepam (1 mg kg(-1)) of hexobarbital-induced sleeping was not modified by honokiol (0.2-20 mg kg(-1)). These results suggest that honokiol is less likely than diazepam to induce physical dependence, central depression and amnesia at doses eliciting the anxiolytic effect. It is also considered that honokiol might have no therapeutic effect in the treatment of convulsion.

Chromatographic resolution of ciprofibrate and interaction of the racemate and both enantiomers with rat liver microsomes in vitro

The enantiomers of ciprofibrate may be achieved by enantioselective HPLC separation of its methylesters using a OD - Daicel column. Ciprofibrates (racemate and both enantiomers) bind to oxidized cytochrome P-450 in rat liver microsomes according type II like aniline or most probably as inversed type I, but less pronounced and with a general shift to the left. Ethylmorphine N-demethylation, ethoxycoumarin and ethoxyresorufin O-deethylation are all inhibited by the ciprofibrates, most effectively ethoxyresorufin O-deethylation by S(-)-ciprofibrate even in microM concentrations. Microsomal luminol and lucigenin amplified chemiluminescence indicating the formation of reactive oxygen species, microsomal hydrogen peroxide formation and NADPH/Fe stimulated lipid peroxidation were inhibited in a concentration dependent manner in concentration ranges between mM and microM. This might be due to distinct scavenger activities of all 3 compounds: the zymosan stimulated chemiluminescence of whole blood was completely inhibited in mM concentrations and influenced significantly down to concentrations of 10 microM, whereas burst and phagocytosis tests with human polynuclear leucocytes were not influenced.

Development of physical dependence to lorazepam in rats: the effects of repeated short treatments, dose and age

Rats were treated with lorazepam for four days (six times 2 mg kg(-1)) at the ages of 71, 118, 163 and 210 days. Increased excitation (physical dependence) in the withdrawal period was tested several times during 14 days with hexobarbital in an EEG threshold test. Lorazepam could induce physical dependence usually with a maximum (20% of the controls) on day four of withdrawal, but the age was a critical variable. A dose-response relationship with regard to lorazepam (0.5, 1, 2 mg kg(-1)) was found at 71 days but a more complicated pattern was found at 118 days of age. The rats treated with lorazepam 2 mg kg(-1) at the ages of either 71 and 118 days were given a treatment again with lorazepam 2 mg kg(-1) three months later. Compared with age-matched untreated rats, previous drug exposure influenced the pattern of increased excitation indicating a carry-over effect even after such a recovery period.

A study of the duration of acute tolerance induced with hexobarbital in male rats

Male rats were infused i.v. with hexobarbital to obtain a burst suppression of 1 s or more in the EEG (SS). At SS the rats were killed and the concentration of hexobarbital was determined by HPLC in three parts of the brain. Acute tolerance (induced by a 1-h exposure at the SS level) was recorded as an approximately 20% increase in brain concentrations of hexobarbital at the last SS during the exposure when compared with concentrations recorded at the first SS in the controls. Increased brain concentrations (approximately 8%) at SS were recorded 24 h after induction of acute tolerance. After 48 h the increase was uncertain. Thus, acute tolerance to hexobarbital could have cumulative properties if new exposures are imposed after 24 h.

Anxiolytic and side-effect profile of LY354740: a potent, highly selective, orally active agonist for group II metabotropic glutamate receptors

LY354740 is a conformationally constrained analog of glutamate which is a potent agonist for group II cAMP coupled metabotropic glutamate receptors (mGluRs). The discovery of this novel pharmacological agent has allowed the exploration of the functional consequences of activating group II mGluRs in vivo. In an effort to evaluate the clinical utility of LY354740 as an anxiolytic, we examined its effects in the fear potentiated startle and elevated plus maze models of anxiety and compared the results with the clinically prescribed anxiolytic diazepam. In the fear potentiated startle and elevated plus maze models, both LY354740 and diazepam produced significant anxiolytic activity (ED50 values of 0.3 and 0.4 mg/kg p. o. for fear potentiated startle and 0.2 and 0.5 mg/kg for the elevated plus maze, respectively). The duration of pharmacological effect for LY354740 in the efficacy models was 4 to 8 hr. In contrast to diazepam, acute administration of LY354740 did not produce sedation, cause deficits in neuromuscular coordination, interact with central nervous system depressants, produce memory impairment or change convulsive thresholds at doses 100- to 1000-fold the efficacious doses in animal models of anxiety. Thus, LY354740 has anxiolytic activity in animal models that are sensitive to benzodiazepines such as diazepam. However, at anxiolytic doses in these models, LY354740 produced none of the unwanted secondary pharmacology associated with diazepam. These data indicate a functional role for group II mGluRs in fear/anxiety responses in animals and suggest that compounds in this class may be beneficial in the treatment of anxiety-related disorders in humans without the side effects seen with currently prescribed medications.

Studies on the sedative effect of Cistanche deserticola

In this study, we investigated the sedative effect of Cistanche deserticola Ma. (CD) on hexobarbital-induced sleeping time in mice and spontaneous motor activity by using automated activity meter in rats. It was found that crude extract of CD could prolong the hexobarbital-induced sleeping time and reduce spontaneous motor activity, including horizontal activity, ambulatory time and total distance. Then the water fraction of CD extract could prolong the hexobarbital-induced sleeping time and reduce the spontaneous motor activity more than that of the other fraction of CD extract in rats. These results suggest that CD ethanol extract and its water fraction possessed the sedative effect.

Synthesis and pharmacological activity of two derivatives of the amide of valproic acid

Valproic acid (VPA), a synthetic branched-chain fatty acid, and its pro-drug the primary amide (VPD) are effective and widely used anti-epileptic agents. Although the use of VPA has grown in recent years, major side effects are still associated with this drug. We presume that it is possible, without loosing the VPD pharmacological profile, to obtain new compounds by undertaking substitutions in the CONH group. N,N'-bis-(2-propylpentanoyl)- 1,2-ethanediamine (3) and N,N'-bis-(2-propylpentanoyl)-1,3-propanediamine (4) were obtained from VPA (1) using a method reported in the literature. The chemical structures of the new compounds were demonstrated by elemental analysis, IR, and 1H NMR spectroscopy. Both compounds are less toxic and more effective in protecting the animals from death caused by PTZ than VPD after intraperitoneal administration to mice.

Pentobarbital decreases the gamma-aminobutyric acidA receptor subunit gamma-2 long/short mRNA ratio by a mechanism distinct from receptor occupation

Treatment with pentobarbital of primary cultured cerebellar granule cells decreased the gamma-aminobutyric acid, (GABA)A receptor subunit gamma-2 long/short (gamma-2L/S) mRNA ratio. A high dose of pentobarbital (500 microM) decreased the gamma-2L/S ratio by 64%; the decrease was dose and time dependent and reversible. (-)-Hexobarbital (500 microM), the less potent stereoisomer for GABA(A) receptor activation, decreased the ratio slightly (30%) but significantly more than (+)-hexobarbital (20%). Other GABA(A) receptor activators had no (100 mM ethanol) or little (2 microM 5alpha-pregnane-3alpha-ol-20-one) effect on the gamma-2L/S ratio. Furthermore, picrotoxin (10 microM), which blocks the GABA- and pentobarbital-activated GABA(A) receptor channel, neither changed the gamma-2L/S ratio nor blocked the pentobarbital-induced changes. These data suggest that barbiturates alter the gamma-2L/S mRNA ratio by a mechanism that does not require GABA(A) receptor activation. The gamma-2L/S subunit mRNA includes an exon encoding an octapeptide that contains a protein kinase C phosphorylation consensus site. This exon-encoded peptide, occurring in the putative intracellular loop, can be phosphorylated, and in vitro, this phosphorylation has been shown to have functional consequences. This is the first report of a drug-induced alteration in receptor mRNA splicing. Furthermore, the changes in the gamma-2L/S ratio produced by pentobarbital exposure may have significant effects on the function of an important brain protein, the GABA(A) receptor.

Pharmacological studies on the novel antiallergic agent HSR-609: its effects on behavior in mice and electroencephalograms in rabbits

We studied the central nervous system (CNS) effects of HSR-609 (3-[4-(8-fluoro-5,11-dihydrobenz[b]oxepino[4,3-b]pyridin-11- ylidene) piperidino]propionic acid dihydrate), a novel amphoteric antiallergic agent having antihistaminic activity. Its effects on the behavior of mice and the electroencephalograms (EEG) of unanesthetized and unrestrained rabbits after oral administration were compared with those of typical antiallergic agents and the non-amphoteric basic compound PY-608 (8-fluoro-5,11-dihydro-11-(1-methyl-4-piperidylidene)benz [b]oxepino[4,3-b]pyridine), which has chemical structure similar to that of HSR-609. HSR-609 (3-300 mg/kg) had no effect on general behavior, spontaneous locomotor activity, hexobarbital-induced sleeping time and reserpine-induced hypothermia in mice. HSR-609 (10-100 mg/kg) and terfenadine (100 mg/kg) had no effect on spontaneous EEG, sleep-wakefulness cycles and EEG power spectra in rabbits. On the other hand, cyproheptadine (3-30 mg/kg), ketotifen (30-100 mg/kg) and PY-608 (0.3-100 mg/kg) caused increases and/or decreases of spontaneous locomotor activity, prolongation of hexobarbital-induced sleeping time and antagonistic effects on reserpine-induced hypothermia in mice. These agents (30 mg/kg) increased slow wave sleep and enhanced EEG power spectra at low frequency bands such as delta and theta in rabbits. These findings suggest that HSR-609 has no inhibitory effect on the CNS due to its amphoteric chemical structure.