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An efficient, five-step synthetic approach to various acyclic 1,3-diamines has been developed and applied to the preparation of a novel class of open-chained fentanyl analogues. The acyclic derivatives 5.15.5 (all new compounds) were synthesized with the aim of estimating the significance of the piperidine ring for the opioid analgesic activity of anilido-piperidines. The starting b-keto-amide 1.1, prepared by the aminolysis of methyl acetoacetate with methylphenethylamine, (93 % yield), was successively reacted with NaH and BuLi, to form the highly reactive a,g-dienolate anion 1.1a. Regio and chemoselective g-alkylation of the dienolate with various primary and secondary alkyl halides furnished the b-keto-amides 1.21.5 (7691 %). Reductive amination of the keto-amides 1.11.5 with aniline and Zn powder in acetic acid, via the enamine intermediates 2.12.5, afforded the b-anilino amides 3.13.5 (7485 %). After reductive deoxygenation of the tertiary amide group, using in situ generated diborane, the corresponding 1,3-diamines 4.14.5 were obtained (8797 %). The synthesis of (±)-2,3-seco-fentanyls 5.15.5 was completed by N-acylation of the diamines 4.14.5 with propionyl chloride, followed by precipitation of the monooxalate salts (8695 %). The parent compound, 2,3-seco-fentanyl 5.1, was found to be a 40 times less potent narcotic analgesic than fentanyl but still 56 times more active than morphine in rats, while i-Pr derivative 5.3 was inactive. Apart from the pharmacological significance, the general procedure described herein may afford various functionalized, 1,3-diamines as potential complexing agents and building blocks for the synthesis of aza-crown ethers.

A general, five step method for the synthesis of 3-alkylfentanyl analogues (i.e., cis and trans 3-alkyl-4-anilidopiperidines 6.16.6) has been developed. The starting N-phenethyl-4-piperidone 1 was first converted into the cyclohexylimine derivative 2, a-deprotonated with butyllithium and the resulting imine anion efficiently monoalkylated with primary and secondary alkyl halides. After mild acid hydrolysis, the obtained 3-alkyl-4-piperidones 3.13.6 were isolated in good yields (7985 %), then condensed with aniline to form imines 4.14.6. Subsequent reduction of the imines (LiAlH4/THF) yielded cis/trans mixtures of 3-alkyl-4-anilinopiperidines 5.15.6. Quantitative separation of the diastereoisomers by column chromatography of Al2O3 gave pure cis 5.15.6 (2951 % yield) and trans 5.15.6 (1927 % yield), with the cis/trans ratio in the range 7/36/4. The synthesis was concluded by N-acylation of the purified 5.15.6, with propionyl chloride, to afford cis and trans 3-alkyl-4-anilidopiperidines 6.16.6 (~95 % yield, as monooxalate salts). No enatioseparation was attempted at any stage. The relative cis/trans stereochemistry was provisionally assigned from the 1H-NMR spectra. Of the twelve synthesized 3-alkylfentanyls, ten compounds (two known and eight novel derivatives, all as the monooxalate salts) were preliminarily tested as analgesics in rats, comparing the potency to fentanyl. Except for the known (±)-cis-3-Me fentanyl 6.1cis, (8 × fentanyl), and the novel (±)-cis-3-Et fentanyl 6.2cis, (1.5 × fentanyl), all of the others were less active than fentanyl or inactive. Some tentative conclusions on the structure-activity relationship (SAR) in this series of derivatives have been made.

The optimum conditions were found for the preconcentration of trace metals in natural waters and model samples with standard metals concentrations by using 4-morpholinedithiocarbamate. The formed complexes were extracted with chloroform. Different methods for recovering the metals from the organic solvent were studied and compared before AAS metal analysis. The developed preconcentration method was successfully applied to the determination of trace metals concentrations in water samples from the Barje lake (Leskovac, Yugoslavia).

The lead concentrations in the water of the Barje lake are presented for the years 1995 to 1998. Sequential extraction was applied to estimate the chemical association of lead in the sediments of the Barje lake. Several lead fractions showed highly significant correlations with the corresponding substrate (step II: Mn-oxyhydroxides; step III: Fe-oxyhydroxides) suggesting that lead carbonates were incorporated with amorphous iron and manganese hydroxides. An explanation for this relation can be in the same anthropogenic source of these elements.

Can nonhuman animals be used for the benefit of humans in a scientifically and morally justified manner and, if yes, how? Based on our own experiences as scholars from various academic backgrounds, we argue that this question can only be answered as an interdisciplinary and international endeavor, considering insights from research ethics and animal ethics as well as scientific and legal aspects. The aim of this article is to contribute to the foundation of the emerging field of animal research ethics. In doing so, we describe the following seven phases of animal research experiments: ethical, legal and social presumptions (phase 0), planning (phase I), review (phase II), conduct of experiments (phase III), publication/dissemination (phase IV), further exploitation of results (phase V), and evaluation (phase VI). In total, 20 key ethical, legal, and practical challenges that an ethical framework for the use of animals in research needs to address are identified and analyzed. Finally, we characterize the following four meta-challenges and opportunities associated with animal research ethics as a field: (1) moral pluralism, (2) the integration of views and positions outside the laboratory, (3) international plurality of conduct, standards, and legal norms, and (4) interdisciplinary education.

Sepsis-induced multiple organ dysfunction arises from the highly complex pathophysiology encompassing the interplay of inflammation, oxidative stress, endothelial dysfunction, mitochondrial damage, cellular energy failure, and dysbiosis. Over the past decades, numerous studies have been dedicated to elucidating the underlying molecular mechanisms of sepsis in order to develop effective treatments. Current research underscores liver and cardiac dysfunction, along with acute lung and kidney injuries, as predominant causes of mortality in sepsis patients. This understanding of sepsis-induced organ failure unveils potential therapeutic targets for sepsis treatment. Various novel therapeutics, including melatonin, metformin, palmitoylethanolamide (PEA), certain herbal extracts, and gut microbiota modulators, have demonstrated efficacy in different sepsis models. In recent years, the research focus has shifted from anti-inflammatory and antioxidative agents to exploring the modulation of energy metabolism and gut microbiota in sepsis. These approaches have shown a significant impact in preventing multiple organ damage and mortality in various animal sepsis models but require further clinical investigation. The accumulation of this knowledge enriches our understanding of sepsis and is anticipated to facilitate the development of effective therapeutic strategies in the future.

Introduction: To prevent mother-to-child transmission (PMTCT) of the human immunodeficiency virus (HIV) during pregnancy, the appropriate dosing regimens of antiretroviral (ARV) drugs need to be determined. Reliable data about pharmacokinetic (PK) characteristics of ARVs from randomized clinical trials (RCTs) are lacking, and post-marketing observational studies may offer valuable, but sometimes insufficient data, especially in pregnant people living with HIV (PLWHIV). This review article is focused PK and toxicological considerations affecting ARV dosing in pregnant PLWHIV., Areas Covered: In our search, we included studies focused on PKs of ARVs in pregnancy available on PubMed, abstracts from recent global conferences and data from modeling studies. There are no significant changes in PKs of nucleoside/nucleotide reverse transcriptase inhibitors and non-nucleoside reverse transcriptase inhibitors throughout pregnancy. In contrast, the PKs of PIs and INSTIs are more variable, especially in the second and third trimesters., Expert Opinion: Pregnant women are left out of RCTs. To the greatest extent possible, future research should include pregnant persons in RCTs, including PK studies, strictly considering maternal and fetal safety. Alternative innovative approaches/models need to be developed to obtain reliable data about rational pharmacotherapy of ARVs in the effective PMTCT of HIV, with maximum safety.

Palmitoylethanolamide (PEA) is an endocannabinoid-like bioactive lipid mediator belonging to the family of N-acylethanolamines, most abundantly found in peanuts and egg yolk. When the gastrointestinal (GI) effects of PEA are discussed, it must be pointed out that it affects intestinal motility but also modulates gut microbiota. This is due to anti-inflammatory, antioxidant, analgesic, antimicrobial, and immunomodulatory features. Additionally, PEA has shown beneficial effects in several GI diseases, particularly irritable bowel syndrome and inflammatory bowel diseases, as various studies have shown, and it is important to emphasize its relative lack of toxicity, even at high dosages. Unfortunately, there is not enough endogenous PEA to treat disturbed gut homeostasis, even though it is produced in the GI tract in response to inflammatory stimuli, so exogenous intake is mandatory to achieve homeostasis. Intake of PEA could be through animal and/or vegetable food, but bearing in mind that a high dosage is needed to achieve a therapeutic effect, it must be compensated through dietary supplements. There are still open questions pending to be answered, so further studies investigating PEA's effects and mechanisms of action, especially in humans, are crucial to implementing PEA in everyday clinical practice.

The control of parasitic nematode infections relies mostly on anthelmintics. The potential pharmacotherapeutic application of phytochemicals, in order to overcome parasite resistance and enhance the effect of existing drugs, is becoming increasingly important. The antinematodal effects of carveol was tested on the free-living nematode Caenorhabditis elegans and the neuromuscular preparation of the parasitic nematode Ascaris suum . Carveol caused spastic paralysis in C . elegans . In A. suum carveol potentiated contractions induced by acetylcholine (ACh) and this effect was confirmed with two-electrode voltage-clamp electrophysiology on the A . suum nicotinic ACh receptor expressed in Xenopus oocytes. However, potentiating effect of carveol on ACh-induced contractions was partially sensitive to atropine, indicates a dominant nicotine effect but also the involvement of some muscarinic structures. The effects of carveol on the neuromuscular system of mammals are also specific. In micromolar concentrations, carveol acts as a non-competitive ACh antagonist on ileum contractions. Unlike atropine, it does not change the EC 50 of ACh, but reduces the amplitude of contractions. Carveol caused an increase in Electrical Field Stimulation-evoked contractions of the isolated rat diaphragm, but at higher concentrations it caused an inhibition. Also, carveol neutralized the mecamylamine-induced tetanic fade, indicating a possibly different pre- and post-synaptic action at the neuromuscular junction., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Stojković, Todorović, Protic, Stevanovic, Medić, Charvet, Marjanović, Nedeljković Trailović and Trailović.)

Alcoholic liver disease (ALD) is a consequence of excessive alcohol use. According to many studies, alcohol represents a significant socioeconomic and health risk factor in today's population. According to data from the World Health Organization, there are about 75 million people who have alcohol disorders, and it is well known that its use leads to serious health problems. ALD is a multimodality spectrum that includes alcoholic fatty liver disease (AFL) and alcoholic steatohepatitis (ASH), consequently leading to liver fibrosis and cirrhosis. In addition, the rapid progression of alcoholic liver disease can lead to alcoholic hepatitis (AH). Alcohol metabolism produces toxic metabolites that lead to tissue and organ damage through an inflammatory cascade that includes numerous cytokines, chemokines, and reactive oxygen species (ROS). In the process of inflammation, mediators are cells of the immune system, but also resident cells of the liver, such as hepatocytes, hepatic stellate cells, and Kupffer cells. These cells are activated by exogenous and endogenous antigens, which are called pathogen and damage-associated molecular patterns (PAMPs, DAMPs). Both are recognized by Toll-like receptors (TLRs), which activation triggers the inflammatory pathways. It has been proven that intestinal dysbiosis and disturbed integrity of the intestinal barrier perform a role in the promotion of inflammatory liver damage. These phenomena are also found in chronic excessive use of alcohol. The intestinal microbiota has an important role in maintaining the homeostasis of the organism, and its role in the treatment of ALD has been widely investigated. Prebiotics, probiotics, postbiotics, and symbiotics represent therapeutic interventions that can have a significant effect on the prevention and treatment of ALD.

Prostate cancer (PCa) is today the second most common cancer in the world, with almost 400,000 deaths annually. Multiple factors are involved in the etiology of PCa, such as older age, genetic mutations, ethnicity, diet, or inflammation. Modern treatment of PCa involves radical surgical treatment or radiation therapy in the stages when the tumor is limited to the prostate. When metastases develop, the standard procedure is androgen deprivation therapy, which aims to reduce the level of circulating testosterone, which is achieved by surgical or medical castration. However, when the level of testosterone decreases to the castration level, the tumor cells adapt to the new conditions through different mechanisms, which enable their unhindered growth and survival, despite the therapy. New knowledge about the biology of the so-called of castration-resistant PCa and the way it adapts to therapy will enable the development of new drugs, whose goal is to prolong the survival of patients with this stage of the disease, which will be discussed in this review.

The proportion of elderly people in the world population is constantly increasing. With age, the risk of numerous chronic diseases and their complications also rises. Research on the subject of cellular senescence date back to the middle of the last century, and today we know that senescent cells have different morphology, metabolism, phenotypes and many other characteristics. Their main feature is the development of senescence-associated secretory phenotype (SASP), whose pro-inflammatory components affect tissues and organs, and increases the possibility of age-related diseases. The liver is the main metabolic organ of our body, and the results of previous research indicate that its regenerative capacity is greater and that it ages more slowly compared to other organs. With age, liver cells change under the influence of various stressors and the risk of developing chronic liver diseases such as non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), alcoholic steatohepatitis (ASH) and hepatocellular carcinoma (HCC) increases. It has been proven that these diseases progress faster in the elderly population and in some cases lead to end-stage liver disease that requires transplantation. The treatment of elderly people with chronic liver diseases is a challenge and requires an individual approach as well as new research that will reveal other safe and effective therapeutic modalities.

Background: This study aimed to calculate the frequency of elevated liver enzymes in hospitalized patients with coronavirus disease 2019 (COVID-19) infection and to test if liver enzyme biochemistry levels on admission could predict the computed tomography (CT) scan severity score of bilateral interstitial pneumonia., Methods: This single-center study comprised of 323 patients including their demographic data, laboratory analyses, and radiological findings. All the information was taken from electronic health records, followed by statistical analysis., Results: Out of 323 patients, 115 of them (35.60%) had aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) over 40 U/L on admission. AST was the best predictor of CT scan severity score of bilateral interstitial pneumonia (R 2 = 0.313, Adjusted R 2 = 0.299). CT scan severity score in the peak of the infection could be predicted with the value of AST, neutrophils, platelets, and monocytes count (R 2 = 0.535, Adjusted R 2 = 0.495)., Conclusion: AST, neutrophils, platelets, and monocytes count on admission can account for almost half (49.5%) of the variability in CT scan severity score at peak of the disease, predicting the extensiveness of interstitial pneumonia related to COVID-19 infection. Liver enzymes should be closely monitored in order to stratify COVID-19 patients with a higher risk of developing severe forms of the disease and to plan the beforehand step-up treatment.

Acute coronary syndrome (ACS) in patients with COVID-19 is triggered by various mechanisms and can significantly affect the patient’s further treatment and prognosis. The study aimed to investigate the characteristics, major complications, and predictors of mortality in COVID-19 patients with ACS. All consecutive patients hospitalized from 5 July 2020 to 5 May 2021 for ACS with confirmed SARS-Co-2 were prospectively enrolled and tracked for mortality until 5 June 2021. Data from the electronic records for age and diagnosis, matched non-COVID-19 and COVID-19 ACS group, were extracted and compared. Overall, 83 COVID-19 ACS patients, when compared to 166 non-COVID ACS patients, had significantly more prevalent comorbidities, unfavorable clinical characteristics on admission (acute heart failure 21.7% vs. 6.6%, p < 0.01) and higher rates of major complications, 33.7% vs. 16.8%, p < 0.01, and intrahospital 30-day mortality, 6.7% vs. 26.5%, p < 0.01. The strongest predictors of mortality were aortic regurgitation, HR 9.98, 95% CI 1.88; 52.98, p < 0.01, serum creatinine levels, HR 1.03, 95% CI 1.01; 1.04, p < 0.01, and respiratory failure therapy, HR 13.05, 95% CI 3.62; 47.01, p < 0.01. Concomitant ACS and COVID-19 is linked to underlying comorbidities, adverse presenting features, and poor outcomes. Urgent strategies are needed to improve the outcomes of these patients.

A dysregulated and overwhelming response to an infection accompanied by the exaggerated pro-inflammatory state and metabolism disturbance leads to the fatal outcome in sepsis. Previously we showed that meldonium, an anti-ischemic drug clinically used to treat myocardial and cerebral ischemia, strongly increases mortality in faecal-induced peritonitis (FIP) in rats. We postulated that the same mechanism that is responsible for the otherwise strong anti-inflammatory effects of meldonium could be the culprit of the increased mortality. In the present study, we applied the LPS-induced model of sepsis to explore the presence of any differences from and/or similarities to the FIP model. When it comes to energy production, despite some shared similarities, it is evident that LPS and FIP models of sepsis differ greatly. A different profile of sympathoadrenal activation may account for this observation, as it was lacking in the FIP model, whereas in the LPS model it was strong enough to overcome the effects of meldonium. Therefore, choosing the appropriate model of sepsis induction is of great importance, especially if energy homeostasis is the main focus of the study. Even when differences in the experimental design of the two models are acknowledged, the role of different patterns of energy production cannot be excluded. On that account, our results draw attention to the importance of uninterrupted energy production in sepsis but also call for much-needed revisions of the current recommendations for its treatment.

Sepsis is a life-threatening condition caused by the dysregulated and overwhelming response to infection, accompanied by an exaggerated pro-inflammatory state and lipid metabolism disturbance leading to sequential organ failure. Meldonium is an anti-ischemic and anti-inflammatory agent which negatively interferes with lipid metabolism by shifting energy production from fatty acid oxidation to glycolysis, as a less oxygen-demanding pathway. Thus, we investigated the effects of a four-week meldonium pre-treatment on faecal-induced sepsis in Sprague-Dawley male rats. Surprisingly, under septic conditions, meldonium increased animal mortality rate compared with the meldonium non-treated group. However, analysis of the tissue oxidative status did not provide support for the detrimental effects of meldonium, nor did the analysis of the tissue inflammatory status showing anti-inflammatory, anti-apoptotic, and anti-necrotic effects of meldonium. After performing tissue lipidomic analysis, we concluded that the potential cause of the meldonium harmful effect is to be found in the overall decreased lipid metabolism. The present study underlines the importance of uninterrupted energy production in sepsis, closely drawing attention to the possible harmful effects of lipid-mobilization impairment caused by certain therapeutics. This could lead to the much-needed revision of the existing guidelines in the clinical treatment of sepsis while paving the way for discovering new therapeutic approaches.

Thioacetamide (TAA) is widely used to study liver toxicity accompanied by oxidative stress, inflammation, cell necrosis, fibrosis, cholestasis, and hepatocellular carcinoma. As an efficient free radical's scavenger, C60 fullerene is considered a potential liver-protective agent in chemically-induced liver injury. In the present work, we examined the hepatoprotective effects of two C60 doses dissolved in virgin olive oil against TAA-induced hepatotoxicity in rats. We showed that TAA-induced increase in liver oxidative stress, judged by the changes in the activities of SOD, CAT, GPx, GR, GST, the content of GSH and 4-HNE, and expression of HO-1, MnSOD, and CuZnSOD, was more effectively ameliorated with a lower C60 dose. Improvement in liver antioxidative status caused by C60 was accompanied by a decrease in liver HMGB1 expression and an increase in nuclear Nrf2/NF-κB p65 ratio, suggesting a reduction in inflammation, necrosis and fibrosis. These results were in accordance with liver histology analysis, liver comet assay, and changes in serum levels of ALT, AST, and AP. The changes observed in gut microbiome support detrimental effects of TAA and hepatoprotective effects of low C60 dose. Less protective effects of a higher C60 dose could be a consequence of its enhanced aggregation and related pro-oxidant role.

Lipids play an essential role in platelet functions. It is known that polyunsaturated fatty acids play a role in increasing platelet reactivity and that the prothrombotic phenotype plays a crucial role in the occurrence of major adverse cardiovascular events. The ongoing increase in cardiovascular diseases' incidence emphasizes the importance of research linking lipids and platelet function. In particular, the rebound phenomenon that accompanies discontinuation of clopidogrel in patients receiving dual antiplatelet therapy has been associated with changes in the lipid profile. Our many years of research underline the importance of reduced HDL values for the risk of such a rebound effect and the occurrence of thromboembolic events. Lipids are otherwise a heterogeneous group of molecules, and their signaling molecules are not deposited but formed "on-demand" in the cell. On the other hand, exosomes transmit lipid signals between cells, and the profile of such changes can be monitored by lipidomics. Changes in the lipid profile are organ-specific and may indicate new drug action targets.

Lipids play an essential role in both tissue protection and damage. Tissue ischemia creates anaerobic conditions in which enzyme inactivation occurs, and reperfusion can initiate oxidative stress that leads to harmful changes in membrane lipids, the formation of aldehydes, and chain damage until cell death. The critical event in such a series of harmful events in the cell is the unwanted accumulation of fatty acids that leads to lipotoxicity. Lipid analysis provides additional insight into the pathogenesis of ischemia/reperfusion (I/R) disorders and reveals new targets for drug action. The profile of changes in the composition of fatty acids in the cell, as well as the time course of these changes, indicate both the mechanism of damage and new therapeutic possibilities. A therapeutic approach to reperfusion lipotoxicity involves attenuation of fatty acids overload, i.e., their transport to adipose tissue and/or inhibition of the adverse effects of fatty acids on cell damage and death. The latter option involves using PPAR agonists and drugs that modulate the transport of fatty acids via carnitine into the interior of the mitochondria or the redirection of long-chain fatty acids to peroxisomes.

Acute ischemia/reperfusion (I/R) liver injury is a clinical condition challenging to treat. Meldonium is an anti-ischemic agent that shifts energy production from fatty acid oxidation to less oxygen-consuming glycolysis. Thus, we investigated the effects of a 4-week meldonium pre-treatment (300 mg/kg b.m./day) on the acute I/R liver injury in Wistar strain male rats. Our results showed that meldonium ameliorates I/R-induced liver inflammation and injury, as confirmed by liver histology, and by attenuation of serum alanine- and aspartate aminotransferase activity, serum and liver high mobility group box 1 protein expression, and liver expression of Bax/Bcl2, haptoglobin, and the phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells. Through the increased hepatic activation of the nuclear factor erythroid 2-related factor 2, meldonium improves the antioxidative defence in the liver of animals subjected to I/R, as proved by an increase in serum and liver ascorbic/dehydroascorbic acid ratio, hepatic haem oxygenase 1 expression, glutathione and free thiol groups content, and hepatic copper-zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activity. Based on our results, it can be concluded that meldonium represent a protective agent against I/R-induced liver injury, with a clinical significance in surgical procedures.

Wearing face masks is recommended as part of personal protective equipment and as a public health measure to prevent the spread of coronavirus disease 2019 (COVID-19) pandemic. Their use, however, is deeply connected to social and cultural practices and has acquired a variety of personal and social meanings. This article aims to identify the diversity of sociocultural, ethical, and political meanings attributed to face masks, how they might impact public health policies, and how they should be considered in health communication. In May 2020, we involved 29 experts of an interdisciplinary research network on health and society to provide their testimonies on the use of face masks in 20 European and 2 Asian countries (China and South Korea). They reflected on regulations in the corresponding jurisdictions as well as the personal and social aspects of face mask wearing. We analyzed those testimonies thematically, employing the method of qualitative descriptive analysis. The analysis framed the four dimensions of the societal and personal practices of wearing (or not wearing) face masks: individual perceptions of infection risk, personal interpretations of responsibility and solidarity, cultural traditions and religious imprinting, and the need of expressing self-identity. Our study points to the importance for an in-depth understanding of the cultural and sociopolitical considerations around the personal and social meaning of mask wearing in different contexts as a necessary prerequisite for the assessment of the effectiveness of face masks as a public health measure. Improving the personal and collective understanding of citizens' behaviors and attitudes appears essential for designing more effective health communications about COVID-19 pandemic or other global crises in the future.     To wear a face mask or not to wear a face mask?     Nowadays, this question has been analogous     to the famous line from Shakespeare's Hamlet:     "To be or not to be, that is the question."     This is a bit allegorical ,     but certainly not far from the current circumstances     where a deadly virus is spreading amongst us ... Vanja Kopilaš, Croatia., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Martinelli, Kopilaš, Vidmar, Heavin, Machado, Todorović, Buzas, Pot, Prainsack and Gajović.)

The effects of twelve weeks of supplementation with fullerene C 60 olive/coconut oil solution on a broad spectrum of parameters in rats were examined. The tissue bioaccumulation of C 60 was shown to be tissue-specific, with the liver, heart, and adrenal glands being the organs of the greatest, and the kidney, brain, and spleen being the organs of the smallest accumulation. C 60 did not change aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase serum activities level, nor the damage of liver cells DNA. There were no effects of fullerene on prooxidant-antioxidant balance in the liver, kidney, spleen, heart, and brain, nor any visible harmful effects on the liver, heart, aorta, spleen, kidney, and small intestine histology. Fullerene changed the gut microbiota structure towards the bacteria that ameliorate lipid homeostasis, causing a serum triglycerides concentration decrease. However, C 60 significantly increased the insulin resistance, serum ascorbate oxidation, and brain malondialdehyde and advanced oxidation protein products level. The deteriorative effects of C 60 on the brain and serum could be attributed to the specific physicochemical composition of these tissues, potentiating the C 60 aggregation or biotransformation as the key element of its pro-oxidative action., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The neuromuscular system of parasitic nematodes has proven to be an efficient pharmacological target for antihelmintics. Some of the most frequently used antiparasitic drugs are agonists or antagonists of nicotinic acetylcholine receptors (nAChRs). The antinematodal mechanism of action of carvacrol involves the inhibition of parasite muscle contraction. We have examined the interaction of carvacrol with antinematodal drugs that are agonists of different subtypes of nAChRs and monepantel, which is a non-competitive antagonist of this receptor in A. suum. Additionally, we investigated the effect of carvacrol on the muscle type of nAChRs in the mammalian host. As orthosteric agonists of nAChR, pyrantel, morantel and befinijum lead to dose-dependent contractions of the neuromuscular preparation of Ascaris suum. Carvacrol 100 μM decreased the E max of pyrantel, morantel and bephenium by 29%, 39% and 12 %, 39 % and 12 % respectively. The EC 50 ratio was 3.43, 2.95 and 2.47 for pyrantel, morantel and bephinium, respectively. Carvacrol 300 u μM reduces the E max of pyrantel, morantel and bephenium by 71%, 80% and 75 %, 80 % and 75 % respectively. The EC 50 ratio for pyrantel, morantel and bephenium was 3.88, 3.19 and 4.83 respectively. Furthermore, carvacrol enhances the inhibitory effect of monepantel on A. suum contractions, which may have an effective clinical application. On the other hand, tested concentrations of carvacrol did not significantly affect the EFS-induced contractions of the rat diaphragm, indicating a lack of interaction with the postsynaptic nAChR at the muscle end plate in mammals, but the highest concentration (300 μM) caused a clear tetanic fade. Carvacrol exhibited a time and dose-dependent effect on the Rota-rod performances of rats with a high value of the ED 50 (421.6 mg/kg). In our research, carvacrol dominantly exhibited characteristics of a non-competitive antagonist of nAChR in A. suum, and enhances the inhibitory effect of monepantel. The combination of monepantel and carvacrol may be clinically very effective, and the carvacrol molecule itself can be used as a promising platform for the development of new anthelmintic drugs., Competing Interests: Declaration of Competing Interest The authors have declared that no competing interests exist., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Acute renal ischemia/reperfusion (I/R) injury is a clinical condition that is challenging to treat. Meldonium is an anti-ischemic agent that shifts energy production from fatty acid oxidation to less oxygen-consuming glycolysis. Thus, in this study we investigated the effects of a four-week meldonium pre-treatment (300 mg/kg b.m./day) on acute renal I/R in male rats (Wistar strain). Our results showed that meldonium decreased animal body mass gain, food and water intake, and carnitine, glucose, and lactic acid kidney content. In kidneys of animals subjected to I/R, meldonium increased phosphorylation of mitogen-activated protein kinase p38 and protein kinase B, and increased the expression of nuclear factor erythroid 2-related factor 2 and haeme oxygenase 1, causing manganese superoxide dismutase expression and activity to increase, as well as lipid peroxidation, cooper-zinc superoxide dismutase, glutathione peroxidase, and glutathione reductase activities to decrease. By decreasing the kidney Bax/Bcl2 expression ratio and kidney and serum high mobility group box 1 protein content, meldonium reduced apoptotic and necrotic events in I/R, as confirmed by kidney histology. Meldonium increased adrenal noradrenaline content and serum, adrenal, hepatic, and renal ascorbic/dehydroascorbic acid ratio, which caused complex changes in renal lipidomics. Taken together, our results have confirmed that meldonium pre-treatment protects against I/R-induced oxidative stress and apoptosis/necrosis., Competing Interests: The authors declare no conflict of interest.

Bacterial purulent meningoencephalitis (BPME) is a life-threatening infectious disease caused by various pyogenic bacteria. The disease is defined as the inflammatory process of leptomeninges (visceral layer, pia mater and arachnoid membrane) and brain parenchyma with exudates in the subarachnoid space and surrounding brain structures. The aim of the study was to define the predisposing factors responsible for the occurrence of BPME, as well as the possible correlation between the presence of predisposing factors and patient demographic characteristics, etiology and outcome of the disease. This retrospective-prospective study included 90 patients with BPME confirmed by clinical, neuroradiological and laboratory findings. Multivariate logistic regression models were fitted to analyze the impact of the predisposing factors on the disease outcomes. Predisposing factors that were related to BPME were found in 61% of patients. Cranial trauma as the leading factor was recorded in 23.3% of patients, followed by previous neurological disease in 14.4% of patients, while 13 patients were exposed to previous chemotherapy or long-term corticosteroid therapy. Cardiovascular diseases were reported in 12.2% and diabetes in 7.8% of patients. The existence of cardiovascular diseases significantly influenced unfavorable outcome of the disease, i.e. ”deceased” in comparison to ”cured” (OR=8.418; 95% CI=1.007-76.270), independently of age and gender. None of the examined predisposing factors was significantly related to the ”recovered with sequels” outcome as compared with ”cured” outcome. Older age and presence of cardiovascular disease as a predisposing factor significantly increased the odds of the BPME unfavorable outcome ”deceased” as compared to ”cured” outcome.

The aim of the present study was to undertake a study on the prevalence of cytochrome P450 2D6 (CYP2D6) poor metabolizer alleles (*3, *4, *5, and *6) on a Montenegrin population and its impact on developing adverse drug reactions (ADRs) of β-blockers in a hospitalized cardiac patient population. A prospective study was conducted in the Cardiology Center of the Clinical Center of Montenegro and included 138 patients who had received any β-blocker in their therapy. ADRs were collected using a specially designed questionnaire, based on the symptom list and any signs that could point to eventual ADRs. Data from patients' medical charts, laboratory tests, and other available parameters were observed and combined with the data from the questionnaire. ADRs to β-blockers were observed in 15 (10.9%) patients. There was a statistically significant difference in the frequency of ADRs in relation to genetically determined enzymatic activity (P<0.001), with ADRs' occurrence significantly correlating with slower CYP2D6 metabolism. Our study showed that the adverse reactions to β-blockers could be predicted by the length of hospitalization, CYP2D6 poor metabolizer phenotype, and the concomitant use of other CYP2D6-metabolizing drugs. Therefore, in hospitalized patients with polypharmacy CYP2D6 genotyping might be useful in detecting those at risk of ADRs.

Background: Adverse drug reactions (ADRs) have a significant impact on human health and health care costs. The aims of our study were to determine the profile of rheumatology patients willing to report ADRs and to identify bias in such a reporting system., Methods: Semi-intensive ADRs reporting system was used in our study. Patients willing to participate (N=261) completed the questionnaire designed for the purpose of the study at the hospital admission. They were subsequently classified into two groups according to their ability to identify whether they had experienced ADRs during the previous month. Group 1 included 214 out of 261 patients who were able to identify ADRs, and group 2 consisted of 43 out of 261 patients who were not able to identify ADRs in their recent medical history., Results: Group 1 patients were more significantly aware of their diagnosis than the patients from group 2. Marginal significance was found between rheumatology patients with and without neurological comorbidities regarding their awareness of ADRs. The majority of patients reported ADRs of cytotoxic drugs. The most reported ADRs were moderate gastrointestinal discomforts., Conclusion: We may draw a profile of rheumatological patients willing to report ADRs: 1) The majority of them suffer from systemic inflammatory diseases and are slightly more prone to neurological comorbidities. 2) They are predominantly aware of their diagnosis but less able to identify the drugs that may cause their ADRs. 3) They tend to report mainly moderate gastrointestinal ADRs; that is, other cohorts of patients and other types of ADRs remain mainly undetected in such a reporting, which could represent a bias. Counseling and education of patients as well as developing a network for online communication might improve patients' reporting of potential ADRs.

Background/aim: Adverse drug reactions (ADRs) appear more frequently than actually reported and registered. The main goal of our work was to analyze risk factors, incidence and characteristics of ADRs in hospitalized cardiac patients., Methods: This prospective study included 200 patients, hospitalized at Cardiology Center of the Clinical Centre of Montenegro. ADRs were collected using specially designed questionnaire, based on the list of symptoms and signs that could point out to potential ADRs. Data from medical charts of patients, lab tests and other available parameters were observed and combined with the data from questionnaire. Severity of ADRs were assessed as serious or nonserious according to the World Health Organization criteria. Causality was assessed using the Naranjo probability scale., Results: A total of 34% of all the patients experienced at least one ADR. The most common ADRs occurred as nervous system disorders, less frequent were cardiovascular disorders, while the immune system disorders were the rarest. Sixteen percent of all ADRs were characterized as serious, most often caused by carvedilol and amiodarone. The majority of patients (97.3%) recovered without consequences. The multivariate analysis showed independent significant associations between ADRs and age, gender, comorbidities and polypragmasia., Conclusion: ADRs represent a significant issue in hospitalized cardiac patients population. The most significant predictors for ADRs in observed population were age, comorbidity, number of medications used during hospitalization and patients' gender. Preventive measures such as pharmacotherapy rationalization and continual education of health care professionals could reduce the frequency of ADRs appearance in patients with detected risk factors.

What Is Known and Objective: Drug-induced thrombocytopenia (DITP) may be a fatal adverse reaction to many drugs. It is often misdiagnosed as primary immune thrombocytopenia (ITP), and thus diagnosis can be delayed and patients can be treated inappropriately. Amlodipine a calcium-channel blocker, and simvastatin, a statin, have very rarely been implicated in DITP. We report on an investigation of the causal relationship of amlodipine and simvastatin with thrombocytopenia occurring in the same patient, and review the literature., Case Summary: We present the case of a 78-year-old female hypertensive diabetic patient with three successive DITPs. The first attack of acute severe thrombocytopenia occurred after a 2-week course of amlodipine, and was initially misdiagnosed as ITP. Her platelet count normalized after the amlodipine was discontinued. The second attack followed her restarting simvastatin 3 weeks later. She had stopped it 2 months earlier having previously taken it for over 5 years. Again, she recovered once the simvastatin was discontinued. The third DITP attack occurred when she accidently took a single dose of amlodipine 9 months later., What Is New and Conclusion: We provide clear evidence of a causal association of amlodipine with thrombocytopenia, and probable evidence of a causal association of simvastatin with thrombocytopenia. This is the first reported case of DITPs occurring with two of the most widely prescribed drugs in the same patient. Many hypertensive patients need to take multiple drugs in order to achieve their treatment goals and this increases their risk of drug-induced adverse reactions and makes identification of the causal drug (or drugs) extremely difficult., (© 2013 Blackwell Publishing Ltd.)

Background/aim: Selective serotonin reuptake inhibitors are the most commonly chosen antidepressants in patients with Parkinson's disease (PD). The aim of our study was to assess the influence of fluoxetine (Flu) on motor functions in patients with PD., Methods: In this prospective, controlled, open-label study, 18 patients with PD and mild depression [(10 < or = Hamilton Rating Scale for Depression (HDRS) < or = 23)] without dementia [(25 < or = Mini-Mental State Examination (MMSE)] were treated with Flu. Both single and repeated dose effects of Flu were assessed on days 1-80. Plasma concentrations of Flu and norfluoxetine (NORFlu) were correlated with the results of selected motor function performance scores: The Unified Parkinsons Disease Rating Score (UPDRS), Finger Tapping Test (FTT) and Purdue Pegboard Test (PPT). Severity of PD, depression and dementia were evaluated using standard tests [(Hoehn and Yahr stages (HY), activity of daily living (ADL), UPDRS, HDRS, MMSE)]., Results: Steady-state for Flu/NORFlu was reached after 18 days of treatment. Such a plateau correlated with significant improvements in both scores of depression and Parkinson's disability (HDRS, UPDRS and ADL, respectively). In addition, FTT and PPT scores also increased until day 18, with further slight fluctuations around the plateau. Optimal motor performances correlated with Flu concentrations of approximately 60-110 microg/L., Conclusion: Flu (20 mg/day) significantly reduced depression in PD patients while it did not impair their motor performances. Because substantial placebo effects may arise in studies of PD and depression, large, prospective, randomized, placebo-controlled clinical trials are warranted.

The objective of this research was to analyse the varicella patients' data in order to determine the following: general frequency of pneumopathies and types of lung changes according to X-ray presentation and the changes on the computed tomography. It examined 101 patients with the clinical presentation of varicella and some of the X-ray entities of varicella pneumopathies. Radiological techniques included chest X-ray and CT scans. Familiarity with clinical, laboratory and radiological characteristics of the disease may be of utmost importance for early recognition.

A retrospective study was performed to evaluate the clinical characteristics of nosocomial infections in patients with acute infection of central nervous system (ACNS infections). The study included 1,686 patients admitted to the ICU. Of 1,686 patients, 936 (55.5%) had ACNS infection. Nosocomial infections was confirmed in 221 (23.6%) patients with ACNS infection. The most common risk factors for ICU-acquired nosocomial infections were consciousness disorder, mechanical ventilation and nasogastric tube. The coagulase - negative Staphylococcus aureus was the most frequent isolated pathogen (285 isolates, 56.5%). Results suggest that a persistently high level of therapeutic activity and persistently depressed consciousness after the ICU admission are associated with the occurrence of hospital-acquired infection in critically ill patients hospitalized at a medical ICU.

Fentanyl is the prototype of the 4-anilidopiperidine class of synthetic opioid analgesics. This study was aimed to review the structure-activity-relationship (SAR) of fentanyl analogs substituted in the position 3, or 4 of the piperidine ring. Pharmacological results show that the groups in position 3 of the piperidine ring, which are larger than methyl, severely reduce the analgesic potency compared to fentanyl. It is likely that the steric factor alone (i.e. voluminosity of the group and cis/trans isomerism), rather than the polarity and/or chemical reactivity, plays a crucial role in the analgesic potency of this series. Although the duration of action, in general, does not depend on the stereochemistry, longer action of the most potent 3-alkyl fentanyl analogs such as cis-3-methyl- and cis-3-ethyl fentanyl, is more likely influenced by pharmacodynamic, rather than pharmacokinetic variables. Also, it is possible that the introduction of a functional group such as 3-carbomethoxy reduces the duration of action by altering pharmacokinetic properties. SAR findings obtained by evaluating the neurotoxic effects of fentanyl analogs substituted in the position 3 of the piperidine ring parallel the SAR findings on analgesia in regard to potency and duration of action. This might suggest that similar receptors are involved in producing both antinociceptive and neurotoxic effects of these drugs. It appears that both the potency and the duration of action in the series of fentanyl analogs substituted in position 4 of the piperidine ring is influenced only by the steric requirement and not by the chemical nature of the substituent.

An interpretative strategy (factorial design experimentation+total resolution analysis+chromatogram simulation) was employed to optimize the separation of 16 polycyclic aromatic hydrocarbons (PAHs) (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, indeno(1,2,3-c,d)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene) in temperature-programmed gas chromatography (GC). Also, the retention behavior of PAHs in the same GC system was studied by a feed-forward artificial neural network (ANN). GC separation was investigated as a function of one (linear temperature ramp) or two (linear temperature ramp+the final hold temperature) variables. The applied interpretative approach resulted in rather good agreement between the measured and the predicted retention times for PAHs in both one and two variable modeling. The ANN model, strongly affected by the number of input experiments, was shown to be less effective for one variable used, but quite successful when two input variables were used. All PAHs, including difficult to separate peak pairs (benzo(k)fluoranthene/benzo(b)fluoranthene and indeno(1,2,3-c,d)pyrene/dibenzo(a,h)anthracene), were separated in a standard (5% phenyl-95% dimethylpolysiloxane) capillary column at an optimum temperature ramp of 8.0 degrees C/min and final hold temperature in the range of 260-320 degrees C.

The hydro-alcoholic extracts of five Equisetum species, E. arvense L., E. sylvaticum L., E. fluviatile L., E. palustre L. and E. telmateia Ehrh., growing-wild in Serbia were evaluated for their genotoxicity, antimicrobial activity, antioxidant capacity and the results related to the total phenol content and HPLC flavonoid profiles. The total phenol content was 92-349 micromol expressed as equivalents of chlorogenic acid per g of dried plant material. Main identified compounds were kaempferol-, quercetin- glycosides and caffeic acid derivatives. E. telmateia extract showed the greatest antioxidant capacity. Almost all tested microorganisms demonstrated some degree of sensitivity to the examined extracts. All tested extracts at 62.5 microg/ml showed higher incidence of micronucleus formation than in the control sample. The obtained data allowed mutual comparison of examined species and their assessment as possible sources of antioxidants, antimicrobials and/or genotoxic substances.

The effect of acute pretreatment with a single dose of simvastatin (1 mg/kg, i.v.; 30 min before ischemia) on renal dysfunction caused by ischemia-reperfusion (I/R) injury in the rat was investigated. I/R injury was induced by clamping both renal vascular pedicles for 45 min, followed by 4 h of reperfusion with saline (2 ml/kg per hour). Simvastatin significantly improved both parameters of glomerular and tubular dysfunction (e.g., creatinine levels and fractional excretion of Na(+), respectively) and especially improved the histological score, compared to control I/R-injured rats treated with saline or 10% DMSO only.

Both methylenetetrahydrofolate (MTHFR) C677T genotype and levodopa treatment may give rise to elevated serum homocysteine levels in parkinsonian patients. We aimed to clarify the interplay of these factors in pathogenesis of Parkinson's disease (PD)-related hyperhomocysteinemia. Total serum levels of homocysteine (tHcy) and MTHFR C677T genotype were investigated in levodopa-treated and -untreated parkinsonian ("de novo") patients, as well as in control healthy subjects matched by age and gender (N=83, 30 and 53, respectively). MTHFR C677T genotypes were equally distributed in PD patients and control subjects, the T allele homozygosity being observed in app. 12-17% cases. tHcy concentrations were significantly higher in both levodopa-treated and -untreated PD patients than in control subjects, and in TT homozygotes than in CT or CC genotype carriers. tHcy levels significantly correlated with the duration of the disease in PD treated patients only, reaching the maximum after 3-6 years. However, there was no correlation between tHcy levels and total daily intake of levodopa in the same group of PD patients. In conclusion, MTHFR C677T genotype is a significant factor for hyperhomocysteinemia in patients with PD, levodopa-untreated and probably even more in levodopa-treated PD patients.

The role of extracellular calcium in the interaction between intracellular cAMP and nitric oxide (NO)/cGMP on the contractility of rat diaphragm pretreated with cumulative concentrations of aminophylline (0.36 - 3.60 mM) was investigated. In a Ca2+-free medium, NG-nitro-L-arginine methyl ester (L-NAME) (1 and 3 mM) depressed tension developed (Td) and also aminophylline-induced potentiation of Td in a concentration-dependent manner. Verapamil (2.5 microM) or nicardipine (20 microM) significantly antagonized the potentiating effect of L-NAME on Td in a calcium-containing medium. However, in the presence of verapamil or nicardipine, L-NAME still produced statistically significant potentiation of the cumulative concentrations of aminophylline (0.36 - 3.60 mM), given in the second series.

The effects of different concentrations of N(G)-nitro-L-arginine methyl ester (L-NAME) (0.3, 1, 3, and 10 mM), a non-selective inhibitor of NOS, on the effect of aminophylline on the isometric contraction of the isolated rat hemidiaphragm were investigated. The muscle contractions were induced by direct subtetanic electrical stimulation. Aminophylline (0.36 - 3.60 mM) produced a typical concentration-dependent increase in both parameters of the isometric contraction: tension developed (Td) and the maximum rate of rise of tension (dT/dt max). The second series of additions of aminophylline produced a more pronounced effect. L-NAME (0.3, 1, 3, and 10 mM, 30 min of incubation without stimulation) itself did not change Td and dT/dt max. However, L-NAME (1, 3, and 10 mM) produced a statistically significant potentiation of the effect of aminophylline on Td and dT/dt max.

Several studies have already indicated some beneficial effects of L-arginine in haemorrhaged rats. The aim of our study was to assess whether intravenous bolus injection of L-arginine could improve some cardiovascular and metabolic parameters in anaesthetized haemorrhaged rabbits (intermittent bleeding; 40% of the estimated blood volume for 15 min). I.v. bolus injection of L-arginine ( 300 mg kg(-1)--L-Arg(300)) increased heart rate (app. 10%) and decreased venous haemoglobin saturation with oxygen (sO(2)) (app. 23%) 60 min after the cessation of bleeding, without changes in arterial pressure. D-arginine (300 mg kg(-1)i.v. bolus-D-Arg(300)) produced similar, but insignificant haemodynamic and metabolic changes. In addition, no difference was found between the effects of the L- and D-isomers. Accordingly, L-arginine produces beneficial effects on the heart rate and tissue oxygen extraction in haemorrhaged rabbits. However, such changes do not appear to be stereospecific., (Copyright 2001 Academic Press.)

The influence of higher environmental temperature (HET=30/-1 degrees C) on fentanyl-induced behavior was studied in unrestrained rats. Subacute exposure (3 days) of rats to HET significantly (P<0.01) increased the cataleptic effect of fentanyl citrate (0.5 mg/kg), in comparison to the corresponding exposure to normal environmental temperature (NET=22+/-1 degrees C). Also, the hyperthermic response of rats to a low dose of fentanyl citrate (0.2-0.5 mg/kg) was significantly (P<0.01) potentiated, and the hypothermic response to a high dose of fentanyl citrate (1.5 mg/kg) was significantly (P<0.05) attenuated after exposure to HET. Fentanyl-induced hyperexcitability, loss of righting reflex, loss of corneal reflex and analgesia were not significantly affected by HET. This study provides the first evidence on the influence of environmental temperature on drug-induced catalepsy. HET-induced potentiation of the cataleptic response to fentanyl could be the result of an interference with behavioral thermoregulation.

1. The effects of the various doses of NG-nitro-L-arginine methyl ester (L-NAME, 10 and 30 mg/kg) on some cardiovascular and biochemical parameters during the early posthemorrhagic period were studied in anesthetized rabbits subjected to hemorrhagic hypovolemia. 2. Hemorrhagic shock was produced by intermittent bleeding of 40% of the estimated blood volume for 15 min. Blood samples were taken before and after bleeding (0, 15 and 60 min). Simultaneously, the mean arterial pressure (MAP) and the heart rate (HR) were measured. Hemorrhaged rabbits were treated by L-NAME10 or L-NAME30 (10 or 30 mg/kg, i.v. bolus injection, respectively) or the corresponding volumes of saline (0.6 ml, i.v. bolus) immediately after the end of bleeding. 3. The observed cardiovascular parameters (MAP, HR) were significantly reduced after the end of bleeding in all rabbits. 4. The rise of the MAP was significantly more pronounced 30 min after the injection of L-NAME30 in comparison with the corresponding values in the saline (S) group. In contrast, L-NAME10 produced only a small, insignificant increase in the MAP in hemorrhaged rabbits. 5. The L-NAME30-induced rise of the MAP was accompanied by a severe bradycardia, hyperkalemia and an aggravated metabolic acidosis, more severe than the corresponding disturbance of the acid-base status in the S group. The changes in the acid-base parameters were observed both in arterial (pH, excess base) and in venous blood (pH) of hemorrhaged rabbits. 6. In conclusion, the i.v. bolus injection of L-NAME30 (immediately after the end of bleeding) produced a significant increase in the MAP during the first hour after the injury, but the presumable inhibition of the endothelial constitutive nitric oxide synthase during the early posthemorrhagic period resulted in severe cardiovascular and metabolic disturbances.

1. A slow intravenous infusion of L-arginine (3 mg kg-1) lasting one hr produced significant hypotension in urethane-anaesthetized spontaneously hypertensive rats (SHRs). 2. A slow intravenous infusion of NG-nitro-L-arginine methyl ester (L-NAME) (3 mg kg-1 h-1) did not produce any significant change in the mean arterial pressure during infusion. After stopping infusion of L-NAME, a slowly developing increase of the mean arterial pressure was observed during the following 40 min. 3. The pressor response to physostigmine (20, 40 and 80 micrograms kg-1, IV), injected during a slow intravenous infusion of either L-arginine or L-NAME, was not changed. 4. L-arginine and L-NAME depressed the pressor responses to physostigmine, if physostigmine was injected after the end of a 1-hr infusion. 5. Acute pretreatment with increasing doses of physostigmine markedly affected the blood pressure response to L-arginine (i.e., L-arginine-caused hypotension was more pronounced), but only slightly that to L-NAME. 6. In conclusion, L-arginine, as a donor of NO, produced hypotension by itself and also decreased, but not significantly, the central cholinergically-mediated hypertension (CCMH) produced by physostigmine. It is quite possible that the peripheral NO released by L-arginine antagonized the increased adrenergic activity in the CCMH. This does happen in normotensive rats, but to a lesser degree than in SHRs, as shown in the current experiments. 7. Also, our results show that inhibition of endogenous NO biosynthesis using L-NAME does not necessarily lead to pressor response in vivo, at least in SHRs. It is concluded that L-arginine-nitric oxide pathways operate in SHRs, as well as in normotensive Wistar rats, but their role in modulating cholinergically-mediated regulation of the mean arterial pressure is less pronounced in SHRs than in normotensive animals.