bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanistic Studies of Catechol Generation from Secondary Quinone Amines Relevant to Indole Formation and Tyrosinase Activation
Authors: Land Edward J. , Ramsden Christopher A. , Riley Patrick A. , Yoganathan Gnanamoly
Published: July 2003

The biological significance of the spontaneous cyclization and redox reactions of ortho‐quinone amines is that these appear to be the mechanism of formation of the indolic components of melanin and are also involved in the autoactivation of tyrosinase. We have previously shown that activation of tyrosinase is prevented by the formation of a cyclic betaine from a tertiary amine analogue. Evidence is presented to show that cyclization of ortho‐quinones by Michael addition also occurs in the oxidation of secondary catecholamines. Three varieties of cyclic product have been detected and their formation is influenced by the nature of the N‐substituent. Five‐membered betaine rings form directly and, although six‐ and seven‐membered rings also form, a transient spiro isomer of the ortho‐quinone was in some cases detected as an intermediate. The heterocyclic products formed as betaines undergo redox exchange with residual quinone to form the corresponding aminochromes. We have established the kinetic constants of these reactions, either directly by pulse radiolysis measurements or by inference using a computer model of the reaction pathway to fit the observed data. To investigate the potential biological applications of this chemistry the system was also examined by tyrosinase‐catalysed oxidation of the catecholamine substrates in which there is re‐oxidation of the catechol formed by the redox exchange reaction and enables measurement of oxygen utilization stoichiometry. We show that the redox exchange reaction is unaffected by side‐chain modification whereas cyclization is dependent on both electronic and steric factors. In the light of these studies we conclude that the failure of tertiary amine‐derived betaines to undergo redox exchange, and thus block in vitro activation of tyrosinase, is due to the absence of a second exchangeable proton.
The Color Loci of Mice – A Genetic Century
Authors: Bennett Dorothy C. , Lamoreux M. Lynn
Published: July 2003

Color loci in mammals are those genetic loci in which mutations can affect pigmentation of the hair, skin, and/or eyes. In the mouse, over 800 phenotypic alleles are now known, at 127 identified color loci. As the number of color loci passed 100 only recently, we celebrate this ‘century’ with an overview of these loci, especially the 59 that have been cloned and sequenced. These fall into a number of functional groups representing melanocyte development and differentiation, melanosomal components, organelle biogenesis, organelle transport, control of pigment‐type switching, and some systemic effects. A human ortholog has been identified in all cases, and the majority of these human genes are found to be loci for human disorders, often affecting other body systems as well as pigmentation. We expect that a significant number of color loci remain to be identified. Nonetheless, the large number known already provide a treasury of resources for reconstruction of the mechanisms, at the subcellular, cellular and tissue levels, that produce a functional pigmentary system and contribute to the normal development and functioning of many other organ systems. The mutant mice also provide valuable models for the study of human disease.
A Critical Appraisal of Vitiligo Etiologic Theories. Is Melanocyte Loss a Melanocytorrhagy?
Authors: Gauthier Yvon , Andre Muriel Cario , Taïeb Alain
Published: July 2003

Common generalized vitiligo is an acquired depigmenting disorder characterized by a chronic and progressive loss of melanocytes from the epidermis and follicular reservoir. However, the mechanism of melanocyte disappearance has never been clearly understood, and the intervention of cellular and humoral autoimmune phenomena as primary events remains unproven. In this review, is discussed the data supporting the major theories of vitiligo, namely melanocyte destruction (autoimmune, neural and impaired redox status) and melanocyte inhibition or defective adhesion. Based on recent morphologic findings in vivo supporting a chronic detachment and transepidermal loss of melanocytes in common generalized vitiligo, a new theory is suggested proposing melanocytorrhagy as the primary defect underlying melanocyte loss, integrating most of the possible triggering/precipitating/enhancing effects of other known factors.
Establishment and Characterization of a Normal Melanocyte Cell Line Derived from Pig Skin
Authors: Julé Sophia , Bossé Philippe , Egidy Giorgia , Panthier Jean‐Jacques
Published: July 2003

Several minipig strains develop spontaneous malignant melanoma. As a first step toward the analysis of genes involved in the tumoral progression of melanoma in these animal models, we developed culture conditions for pig melanocytes whereby melanocytes from normal epidermis can be isolated directly onto mitotically inactivated keratinocytes in Eagle's minimal essential medium supplemented with fetal calf serum, tetradecanoyl phorbol acetate (TPA) and cholera toxin. We also derived an immortal line of pigmented melanocytes from the epidermis of a healthy Meishan pig. This cell line, designated PigMel, retains differentiation function in culture, dependence on TPA and cholera toxin and a diploid chromosome number. PigMel melanocytes exhibit morphological and molecular characteristics common to normal mammalian skin melanocytes.
Microbiology in diagnosis and treatment planning in periodontics
Authors: Van Winkelhoff A.J.
Published: July 2003

Abstract Periodontitis is considered a multifactorial infectious disease in which bacteria play an essential role. It has become clear that not all patients with periodontitis harbour the same subgingival microflora, and so far, a limited number of species have been recognised as indicators for progression of periodontal breakdown. These findings are the basis for the use of clinical periodontal microbiology. Microbiological information can assist in diagnosis and treatment planning in periodontics, and is essential for the rational use of topical and systemic antimicrobial treatment. Different antimicrobial regimes have been proposed as adjuncts to mechanical periodontal treatment. This article reviews the current knowledge on periodontal microbiology, different techniques to test for marker bacteria and the use of antibiotics in the treatment of severe periodontitis.
Antiviral activity of alcohol for surface disinfection
Authors: Moorer WR
Published: July 2003

Abstract Bacteria and viruses from the patient's mouth travel with dental splatter and spills. A surface disinfectant should possess antiviral activity as well as antibacterial action. Because of frequent and ‘open’ application in the dental office, such a disinfectant should be non‐toxic, non‐allergenic and safe for the hygienist. It now appears that high‐concentration alcohol mixtures (i.e. 80% ethanol + 5% isopropanol) are not only excellent antibacterials, but quickly inactivate HIV as well as hepatitis B and hepatitis C viruses. Compared to alternative surface disinfectants, use of high‐concentration alcohol for the spray‐wipe‐spray method of surface disinfection in dentistry appears safe and efficient. However, dried matter should be wiped and hydrated first.
How to select the right mouthrinses in periodontal prevention and therapy. Part I. Test systems and clinical investigations
Authors: Netuschil L , Hoffmann T , Brecx M
Published: July 2003

Abstract The use of mouthrinses is increasing, especially as adjuncts to the daily mechanical oral hygiene. Different test systems may and can be used to test their antibacterial and clinical effects: bacteriology in vitro, substantivity in vivo, 4‐day plaque re‐growth, experimental gingivitis and long‐term use. The plaque re‐growth investigations of a few days are not only of limited use but may also be dangerous because often too extensive conclusions have been drawn from their design. The ‘gold standard’ test is the experimental gingivitis model to reveal the antiplaque as well as the antigingivitis effects of any mouthrinse preparation during 3 weeks. The last kind of investigations are of several months' duration, where the substances are used as supplements to mechanical oral hygiene measures.
Tongue coating and tongue brushing: a literature review
Authors: Danser M. M , Gómez S. Mantilla , Van der Weijden G. A
Published: July 2003

Abstract The present paper reviews the role of the tongue as a habitat for oral microorganisms and the potential need for tongue cleaning as part of daily oral hygiene. In addition tongue coating is described. Many microorganisms have been found colonizing the dorsum of the tongue. Some studies find a positive effect to tongue brushing on bacterial counts on the tongue. On the other hand there are also studies that do not find any differences in bacterial counts before or after tongue brushing. Bacteria colonizing the tongue and periodontal pockets play an important role in the production of volatile sulphur compounds in periodontal health and disease. These compounds can be the cause of oral malodour. The amount of tongue coating in patients complaining of halitosis was significantly greater than in patients without halitosis. Tongue brushing on a regular basis, particular aiming at removing the coating on the dorsum of the tongue, has been found to be fruitful in reducing oral malodour. Studies investigating the role of tongue brushing and plaque accumulation or gingival inflammation show conflicting results. It is clear that the tongue forms the largest niche for microorganims in the oral cavity. However, on the basis of literature, there appears to be no data to justify the necessity to clean the tongue on a regular basis. One exception would be oral malodour.
Quality assurance in health care: past, present and future
Authors: Bilawka E. , Craig B.J.
Published: July 2003

Abstract Quality of health care delivery is a growing concern globally given current budget restraints and increasing demands on health care providers. The variety of quality assurance and quality management activities equals the numerous ways health care practitioners of all genres provide health care. Dental hygienists around the world must be knowledgeable about quality assurance and management in health care as it is a significant factor in the evolution of the dental hygiene profession and the quality of oral health care provided by dental hygienists. The objective of this research was to conduct a literature review on quality assurance and quality management. A MEDLINE search from 1966 to 2002 was conducted. The search resulted in approximately 145 articles. Additional references from works generated by the search were also obtained. The literature revealed information on the background and history of quality assurance and quality management. Much of the literature was devoted to discussions of the validity, reliability and effectiveness of most prominent quality management activities being utilised in health care today. The investigation revealed numerous issues and barriers surrounding quality management. This article concludes with suggestions for future directions of quality assurance and quality management.
Status of oral healthcare in long‐term care facilities
Authors: Pino A. , Moser M. , Nathe C.
Published: July 2003

Abstract Oral health is a fundamental component in the overall well‐being and quality of life for elders living in long‐term care facilities. Effective oral care interventions must not only involve recognising the importance of oral health in this population, but giving oral hygiene the same priority as other care practices in long‐term care settings.
Oral health care for pregnant and postpartum women
Authors: Goldie M. Perno
Published: July 2003

Abstract Pregnancy may pose a number of concerns to the mother and the foetus. This can include systemic and oral issues that effect health. Transmission of caries‐causing bacteria is one problem that can be minimized by utilizing simple, cost‐effective measures. Chlorhexidine rinses and xylitol containing chewing gum will be discussed as possible solutions to this tremendous public health problem.
Effects of cyclooxygenase inhibitor pretreatment on nitric oxide production, nNOS and iNOS expression in rat cerebellum
Authors: DiGirolamo G , Farina M , Riberio M L , Ogando D , Aisemberg J , de Los Santos A R , Martí M L , Franchi A M
Published: July 2003

The therapeutic effect of nonsteroidal anti‐inflammatory drugs (NSAIDs) is thought to be due mainly to its inhibition of cyclooxygenase (COX) enzymes, but there is a growing body of research that now demonstrates a variety of NSAIDs effects on cellular signal transduction pathways other than those involving prostaglandins.

Nitric oxide (NO) as a free radical and an agent that gives rise to highly toxic oxidants (peroxynitrile, nitric dioxide, nitron ion), becomes a cause of neuronal damage and death in some brain lesions such as Parkinson and Alzheimer disease, and Huntington's chorea.

In the present study, the in vivo effect of three NSAIDs (lysine clonixinate (LC), indomethacine (INDO) and meloxicam (MELO)) on NO production and nitric oxide synthase expression in rat cerebellar slices was analysed. Rats were treated with (a) saline, (b) lipopolysaccharide (LPS) (5 mg kg−1, i.p.), (c) saline in combination with different doses of NSAIDs and (d) LPS in combination with different doses of NSAIDs and then killed 6 h after treatment.

NO synthesis, evaluated by Bred and Snyder technique, was increased by LPS. This augmentation was inhibited by coadministration of the three NSAIDs assayed. None of the NSAIDs tested was able to modify control NO synthesis.

Expression of iNOS and neural NOS (nNOS) was detected by Western blotting in control and LPS‐treated rats. LC and INDO, but not MELO, were able to inhibit the expression of these enzymes.

Therefore, reduction of iNOS and nNOS levels in cerebellum may explain, in part, the anti‐inflammatory effect of these NSAIDs and may also have importance in the prevention of NO‐mediated neuronal injury.

British Journal of Pharmacology (2003) 139, 1164–1170. doi:10.1038/sj.bjp.0705315
Modulation of neuronal nicotinic receptor function by the neuropeptides CGRP and substance P on autonomic nerve cells
Authors: Di Angelantonio Silvia , Giniatullin Rashid , Costa Valeria , Sokolova Elena , Nistri Andrea
Published: July 2003

One classical example of how neuropeptides can affect the function of ligand‐gated receptors is the modulation of neuronal nicotinic receptors (nAChRs) by substance P. The present review updates current understanding of this action by substance P and compares it with other neuropeptides more recently found to modulate nAChRs in the autonomic nervous system.

Calcitonin gene‐related peptide (CGRP) and its N‐terminal fragments have been shown to exert complex inhibitory as well facilitatory actions on nAChRs. Fragments such as CGRP1–4, CGRP1–5 and CGRP1–6 rapidly and reversibly enhance agonist sensitivity of nAChRs without directly activating those receptors. Longer fragments or the full‐length peptide potently inhibit responses mediated by nAChRs via an apparently competitive‐type antagonism. This phenomenon differs from the substance P‐induced block, which is agonist use‐dependent and preferential towards large nicotinic responses.

It is argued that the full‐length peptides CGRP and substance P might play distinct roles in the activity‐dependent modulation of cholinergic neurotransmission, by inhibiting background noise in the case of CGRP or by reducing excessive excitation in the case of substance P. Hence, multiple neuropeptide mechanisms may represent a wide array of fine‐tuning processes to regulate nicotinic synaptic transmission.

The availability of novel CGRP derivatives with a strong enhancing action on nAChRs may offer new leads for the drug design targeted for potentiation of nAChRs in the autonomic nervous system as well as in the brain, a subject of interest to counteract the deficit of the nAChR function associated with neurodegenerative diseases like Alzheimer's and Parkinson's diseases.

British Journal of Pharmacology (2003) 139, 1061–1073. doi:10.1038/sj.bjp.0705337
Muscarinic regulation of cardiac ion channels
Authors: Harvey Robert D , Belevych Andriy E
Published: July 2003

The parasympathetic component of the autonomic nervous system plays an important role in the physiological regulation of cardiac function by exerting significant influence over the initiation as well as propagation of electrical impulses, in addition to being able to regulate contractile force. These effects are mediated in whole or in part through changes in ion channel activity that occur in response to activation of M2 muscarinic cholinergic receptors following release of the neurotransmitter acetylcholine. The coupling of M2 receptor activation to most changes in cardiac ion channel function can be explained by one of two general paradigms. The first involves direct G protein‐dependent regulation of ion channel activity. The second involves indirect regulation of ion channel activity through modulation of cAMP‐dependent responses. This review focuses on recent advances in our understanding of the mechanisms by which M2 muscarinic receptor activation both inhibits and facilitates cAMP‐dependent ion channel responses in the heart.

British Journal of Pharmacology (2003) 139, 1074–1084. doi:10.1038/sj.bjp.0705338
An angiotensin II type 1 receptor antagonist, olmesartan medoxomil, improves experimental liver fibrosis by suppression of proliferation and collagen synthesis in activated hepatic stellate cells
Authors: Kurikawa Nobuya , Suga Miwa , Kuroda Shoko , Yamada Keisuke , Ishikawa Hirokazu
Published: July 2003

We studied the effect of a new angiotensin II type 1 (AT1) receptor antagonist, olmesartan medoxomil (olmesartan), on the fibrogenic responses in rat hepatic stellate cells (HSCs) and liver fibrogenesis.

Olmesartan (1 mg kg−1 per day) was orally administered to fibrotic rats, induced by bile duct ligation. Liver hydroxyproline content, the mRNA expression of collagen α1(I) and α‐smooth muscle actin (α‐SMA), and plasma levels of transforming growth factor‐β1 (TGF‐β1) were significantly reduced by olmesartan treatment, suggesting that olmesartan improved liver fibrosis. Interestingly, AT1 receptors were found to be expressed in α‐SMA‐positive cells in the fibrotic area of livers in bile duct‐ligated rats by immunohistochemical analysis. Olmesartan treatment reduced the number of these cells.

In vitro experiments showed that angiotensin II (Ang II) treatment induced proliferation and collagen synthesis, and upregulated the profibrogenic cytokines, TGF‐β1 and connective tissue growth factor (CTGF), in rat primary HSCs. Olmesartan blocked all these effects of Ang II.

Based on these results, since activated HSCs were found to express AT1 receptors and Ang II is thought to play an important role in the pathogenesis of liver fibrosis by binding to these receptors, olmesartan may act as a potent antifibrotic drug to suppress the proliferation, collagen synthesis and the expression of profibrogenic cytokines in activated HSCs by blocking these receptors.

British Journal of Pharmacology (2003) 139, 1085–1094. doi:10.1038/sj.bjp.0705339
Quantitative autoradiography of adenosine receptors in brains of chronic naltrexone‐treated mice
Authors: Bailey Alexis , Hawkins Rachel M , Hourani Susanna M O , Kitchen Ian
Published: July 2003

Manipulation of μ opioid receptor expression either by chronic morphine treatment or by deletion of the gene encoding μ opioid receptors leads to changes in adenosine receptor expression. Chronic administration of the opioid receptor antagonist naltrexone leads to upregulation of μ receptor binding in the brain.

To investigate if there are any compensatory alterations in adenosine systems in the brains of chronic naltrexone‐treated mice, we carried out quantitative autoradiographic mapping of A1 and A2A adenosine receptors in the brains of mice treated for 1 week with naltrexone (8 mg−1 kg−1 day−1), administered subcutaneously via osmotic minipump.

Adjacent coronal brain sections were cut from chronic saline‐ and naltrexone‐treated mice for the determination of binding of [3H] D‐Ala2‐MePhe4‐Gly‐ol5 enkephalin ([3H] DAMGO), [3H]1,3‐dipropyl‐8‐cyclopentylxanthine ([3H] DPCPX) or [3H] 2‐[p‐(2‐carbonylethyl)phenylethylamino]‐5′‐N‐ethylcarboxamidoadenosine ([3H] CGS21680) to μ, A1 and A2A receptors, respectively.

A significant increase in μ and A1 receptor binding was detected in chronic naltrexone‐treated brains. The changes in μ receptors were significant in several regions, but changes in A1 were relatively smaller but showed significant upregulation collectively. No significant change in A2A receptor binding was detected in chronic naltrexone‐treated brains.

The results show that blockade of opioid receptors causes upregulation of A1 receptors, but not A2A receptors, by as yet undefined mechanisms.

British Journal of Pharmacology (2003) 139, 1187–1197. doi:10.1038/sj.bjp.0705340
Hepatic insulin sensitizing substance: a novel ‘sensocrine’ mechanism to increase insulin sensitivity in anaesthetized rats
Authors: Porszasz Robert , Legvari Gyorgyi , Pataki Tunde , Szilvassy Judith , Nemeth Jozsef , Kovacs Peter , Paragh Gyorgy , Szolcsanyi Janos , Szilvassy Zoltan
Published: July 2003

We recently described the sensory nitrergic nature of the hepatic insulin sensitizing substance (HISS) mechanism linked to postprandial activation of anterior hepatic plexus fibres in rabbits. This study is designed to assess the involvement of the sensory pathways in this mechanism.

Selective sensory denervation of the anterior hepatic plexus (AHP) was achieved by a 3‐day perineurial treatment with 2% capsaicin solution in Wistar rats (230–250 g). After 1 week, hyperinsulinaemic (100 μU kg−1) euglycaemic (5.5 mmol kg−1) glucose clamp studies were performed to estimate insulin sensitivity.

The rats with regional AHP sensory denervation exhibited a significantly decreased insulin sensitivity, that is, 9.1±1.0 mg kg−1 min−1 glucose reinstalled euglycaemia vs 13.3±1.9 mg kg−1 min−1 glucose (P<0.01) in control rats.

Acute partial hepatic denervation by AHP cut was without effect on insulin sensitivity, whereas chronic hepatic denervation induced insulin resistance was similar to that achieved by regional AHP capsaicin treatment.

Intraportal administration of L‐NAME (10 mg kg−1) decreased, whereas capsaicin (0.3 mg kg−1 min−1) increased insulin sensitivity. Neither atropine (1 mg kg−1) nor acetylcholine (1–10 μg mg min−1) produced any significant effect. In animals with preceding regional capsaicin desensitization, none of the pharmacological manoeuvres modified the resulting insulin‐resistant state.

Cysteamine (200 mg kg−1 s.c.) is known to cause functional somatostatin depletion‐induced insulin resistance similar to that produced by either chronic partial hepatic denervation or perineurial AHP capsaicin desensitization. Intraportal capsaicin (0.3 mg kg−1 min−1) was unable to modify insulin resistance achieved by cysteamine.

We conclude that capsaicin‐sensitive sensory fibres play a crucial role in neurogenic insulin sensitization known as the HISS mechanism without involvement of anatomical reflex‐mediated circuits. The results also suggest that HISS is identical to somatostatin of AHP sensory neural origin.

British Journal of Pharmacology (2003) 139, 1171–1179. doi:10.1038/sj.bjp.0705342
Tityustoxin‐K(alpha) blockade of the voltage‐gated potassium channel Kv1.3
Authors: Rodrigues Aldo Rogelis A , Arantes Eliane C , Monje Francisco , Stuhmer Walter , Varanda Wamberto Antonio
Published: July 2003

We investigated the action of TsTX‐Kα on cloned Kv1.3 channels of the Shaker subfamily of voltage‐gated potassium channels, using the voltage–clamp technique. Highly purified TsTX‐Kα was obtained from the venom of the Brazilian scorpion Tityus serrulatus using a new purification protocol. Our results show that TsTX‐Kα blocks Kv1.3 with high affinity in two expression systems.

TsTX‐Kα blockade of Kv1.3 channels expressed in Xenopus oocytes was found to be completely reversible and to exhibit a pH dependence. The KD was 3.9 nM at pH 7.5, 9.5 nM at pH 7.0 and 94.5 nM at pH 6.5.

The blocking properties of TsTX‐Kα in a mammalian cell line (L929), stably transfected to express Kv1.3, were studied using the patch–clamp technique. In this preparation, the toxin had a KD of 19.8 nM at pH 7.4.

TsTX‐Kα was found to affect neither the voltage‐dependence of activation, nor the activation and deactivation time constants. The block appeared to be independent of the transmembrane voltage and the toxin did not interfere with the C‐type inactivation process.

Taken as a whole, our findings indicate that TsTX‐Kα acts as a simple blocker of Kv1.3 channels. It is concluded that this toxin is a useful tool for probing not only the physiological roles of Kv1.2, but also those mediated by Kv1.3 channels.

British Journal of Pharmacology (2003) 139, 1180–1186. doi:10.1038/sj.bjp.0705343
Substance P increases neutrophil adhesion to human umbilical vein endothelial cells
Authors: Dianzani Chiara , Collino Massimo , Lombardi Grazia , Garbarino Giovanni , Fantozzi Roberto
Published: July 2003

Adhesion of neutrophils (PMNs) to vascular endothelial cells (EC) is a critical step in recruitment and infiltration of leukocytes into tissues during inflammation. Substance P (SP), a neuropeptide released from sensory nerves, evoked PMN adhesion to EC. The NK receptor subtype(s) and the cell type(s) involved were investigated.

SP was coincubated with human PMNs and EC from the human umbilical vein (HUVEC); adhesion was quantitated by computerised microimaging fluorescence analysis.

The proadhesive effects of SP (range 10−18–10−6 M) were illustrated in a biphasic dose–response curve, with a maximum at 10−15 M (276±16% adhesion vs control; P<0.01) and another one at 10−10 M (200±18% adhesion vs control; P<0.01). Neurokinin A was less active and neurokinin B was inactive. The adhesion molecules LFA‐1 and OKM‐1, but not selectins, were involved according to results with selective mAbs.

The NK1 agonist [Sar9,Met(O2)11]SP reproduced the effects of SP, whereas the NK2 agonist [βAla8]‐neurokininA (4–10) acted at 10−13–10−8 M only. The NK3 agonist, senktide, was ineffective.

The NK1 antagonists, CP 96,345 and L 703,606 (both 10−6 M), abolished the effect of 10−15 M SP and inhibited that of 10−10 M SP by 56±5% (P<0.01). By comparison, the NK2 antagonist, SR 48,968 (10−7 M), partially antagonised the adhesion evoked by 10−10 M SP (% inhibition: 61±6; P<0.05).

Since preincubation of PMNs and HUVEC with SP gave the same results it is clear that both cell types contributed to its proadhesive effects.

These results indicate that SP induced a proadhesive effect during inflammatory processes, which was mediated by NK1 and NK2 receptors.

British Journal of Pharmacology (2003) 139, 1103–1110. doi:10.1038/sj.bjp.0705344
Role of c‐jun N‐terminal kinase in the induced release of GM‐CSF, RANTES and IL‐8 from human airway smooth muscle cells
Authors: Oltmanns Ute , Issa Razao , Sukkar Maria B , John Matthias , Chung K Fan
Published: July 2003

Human airway smooth muscle cells (HASMC) contribute to airway inflammation in asthma by virtue of their capacity to produce several inflammatory mediators including IL‐8, GM‐CSF and RANTES. The intracellular signal pathway underlying the production of these cytokines in HASMC is not entirely elucidated.

We examined the role of the mitogen‐activated protein kinase (MAPK) c‐jun N‐terminal kinase (JNK) in TNFα‐ and IL‐1β‐induced GM‐CSF, RANTES and IL‐8 production in HASMC by using a novel specific inhibitor for JNK (SP600125).

Confluent HASMC were treated with TNFα or IL‐1β (10 ng ml−1) for 24 h in the presence or absence of SP600125 (1–100 μM). JNK activity was determined by a kinase assay. Phosphorylation of JNK, p38 MAPK and ERK was examined by Western blotting. Culture supernatants were assayed for GM‐CSF, RANTES and IL‐8 content by ELISA.

Maximum TNFα‐ or IL‐1β‐induced phosphorylation of JNK in HASMC occurred after 15 min and returned to baseline levels after 4 h. SP600125 inhibited TNFα‐ and IL‐1β‐induced JNK activity in HASMC as shown by the reduced phosphorylation of its substrate c‐jun. Furthermore, GM‐CSF, RANTES and to a lesser extent IL‐8 release from HASMC treated with TNFα and IL‐1β was inhibited dosedependently by SP600125.

JNK activation is involved in TNFα‐ and IL‐1β‐induced GM‐CSF, RANTES and IL‐8 production from HASMC. JNK may therefore represent a critical pathway for cytokine production in HASMC.

British Journal of Pharmacology (2003) 139, 1228–1234. doi:10.1038/sj.bjp.0705345
The critical role of leukotriene B4 in antigen‐induced mechanical hyperalgesia in immunised rats
Authors: Cunha Joice Maria , Sachs Daniela , Canetti Claudio Azevedo , Poole Stephen , Ferreira Sérgio Henrique , Cunha Fernando Queiroz
Published: July 2003

We investigated the mediators responsible for mechanical hypersensitivity induced by antigen challenge in rats immunised with ovalbumin (OVA).

Challenge with OVA (12.5–100 μg, intraplantar) caused a dose‐ and time‐dependent mechanical hypersensitivity, which peaked 3 h after, decreased thereafter and reached control levels 24 h later.

Levels of TNFα, IL‐1β and cytokine‐induced neutrophil chemoattractant 1 (CINC‐1) were increased in paw skin after antigen challenge.

OVA‐evoked hypersensitivity was partially inhibited (about 51%) by pretreatment with anti‐TNFα, IL‐1β and IL‐8 sera or with IL‐1 receptor antagonist (IL‐1ra), but not anti‐NGF serum. Pretreatment with thalidomide (45 mg kg−1) or pentoxifylline (100 mg kg−1) also partially inhibited the hypersensitivity at 1–3 h after challenge.

Pretreatment with indomethacin (5 mg kg−1) or atenolol (1 mg kg−1) reduced the OVA‐induced hypersensitivity at 1 and 3 h, but not at 5 h after challenge, while the combination of B1 and B2 bradykinin receptor antagonists was ineffective over the same times.

Pretreatment with MK886 (5‐lipoxygenase‐activating protein inhibitor, 3 mg kg−1), CP 105696 (LTB4 receptor antagonist; 3 mg kg−1) or dexamethasone (0.5 mg kg−1) inhibited the hypersensitivity from 1 to 5 h. Furthermore, LTB4 levels were increased in the paw skin of challenged rats.

In conclusion, our results suggest that the TNFα‐, IL‐1β‐ and CINC‐1‐driven release of prostaglandins, sympathetic amines and LTB4 mediates the first 3 h of mechanical hypersensitivity induced by antigen challenge in rats. At 5 h after OVA administration, although TNFα has some role, LTB4 is the critical nociceptive mediator.

British Journal of Pharmacology (2003) 139, 1135–1145. doi:10.1038/sj.bjp.0705346
Delphinidin, an active compound of red wine, inhibits endothelial cell apoptosis via nitric oxide pathway and regulation of calcium homeostasis
Authors: Martin Sophie , Giannone Grégory , Andriantsitohaina Ramaroson , Carmen Martinez M
Published: July 2003

Epidemiological studies have suggested that moderate consumption of natural dietary polyphenolic compounds might reduce the risk of cardiovascular disease and also protect against cancer. The present study investigates the effects of delphinidin, an anthocyanin present in red wine, on bovine aortic endothelial cells apoptosis.

Based on flow cytometry, terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling analysis and detection of mitochondrial cytochrome c release, we show that delphinidin (10−2 g l−1) alone had no effect either on necrosis or on apoptosis, but it significantly reduced apoptosis elicited by actinomycin D (1 μg ml−1, 24 h) and 7β‐hydroxycholesterol (10 μg ml−1, 18 h).

The protective effect of delphinidin was abolished by inhibitors of nitric oxide‐synthase (NOS) (L‐NA, 100 μM and SMT, 100 μM), guanylyl cyclase (ODQ, 100 μM) and MAP kinase (PD98059, 30 μM).

Western blot analysis and protein detection by confocal microscopy demonstrate that the antiapoptotic effect of delphinidin was associated with an increased endothelial NOS expression mediated by a MAP kinase pathway.

Finally, delphinidin alone had no effect on cytosolic‐free calcium ([Ca2+]i), but normalized the changes in [Ca2+]i produced by actinomycin D towards the control values, suggesting that the antiapoptotic effect of delphinidin is associated with the maintenance of [Ca2+]i in the physiological range.

All of the observed effects of delphinidin may preserve endothelium integrity, the alteration of which lead to pathologies including cardiovascular diseases, such as atherosclerosis, and is often associated with cancers. In conclusion, the protective effect of delphinidin against endothelial cell apoptosis contributes to understand the potential benefits of a consumption rich in polyphenols.

British Journal of Pharmacology (2003) 139, 1095–1102. doi:10.1038/sj.bjp.0705347
Acetylcholine and tachykinins involvement in the caffeine‐induced biphasic change in intracellular Ca2+ in bovine airway smooth muscle
Authors: Montaño Luis M , Carbajal Verónica , Arreola José L , Barajas‐López Carlos , Flores‐Soto Edgar , Vargas Mario H
Published: July 2003

Caffeine has been widely used as a pharmacological tool to evaluate Ca2+ release from the sarcoplasmic reticulum in isolated smooth muscle cells. However, in nervous tissue this drug also causes neurotransmitters release, which might cause additional effects when smooth muscle strips are evaluated. To assess this last possibility, simultaneous measurements of contraction and cytosolic Ca2+ concentration (using Fura–2/AM) were carried out in bovine airway smooth muscle strips during caffeine stimulation.

A first stimulation (S1, n=11) with caffeine (10 mM) induced a biphasic change in cytosolic Ca2+, which consisted of a transient Ca2+ peak (254±40 nM, X±SEM) followed by a plateau (92±13 nM), and a transient contraction (204.72±31.56 mg tension mg tissue−1). A second caffeine stimulation (S2) produced a similar response but these parameters had a different magnitude. The S2/S1 ratios for these parameters were 0.69±0.02, 0.83±0.06 and 1.01±0.03, respectively. Addition of ω‐conotoxin GVIA (1 μM) and tetrodotoxin (3.1 μM) before S2 significantly diminished these S2/S1 ratios (0.26±0.05, 0.26±0.09 and 0.64±0.11, respectively, n=5, P<0.05), implicating the neurotransmitters release involvement in the response to caffeine. A similar effect (P<0.01) was observed with atropine (1 μM, n=4), the fragment 4–11 of substance P (SP) (an SP receptor antagonist, 10 μM, n=5), and with both substances (n=4).

We discarded a direct effect of ω‐conotoxin GVIA (1 μM) plus tetrodotoxin (3.1 μM) or of atropine (1 μM) plus SP fragment 4–11 on smooth muscle cells because they did not modify caffeine responses in isolated tracheal myocytes.

We confirmed by HPLC that caffeine increased the release of acetylcholine (from 0.43±0.19 to 2.07±0.56 nM mg tissue−1, P<0.02) in bovine airway smooth muscle strips. Detection of substance P by ELISA was not statistically different after caffeine stimulation (geometric means before and after caffeine, 0.69 vs. 1.97 pg ml−1 mg tissue−1, respectively, P=0.053).

We concluded that acetylcholine and tachykinins release are involved in the caffeine‐induced biphasic changes in cytosolic Ca2+ concentration.

British Journal of Pharmacology (2003) 139, 1203–1211. doi:10.1038/sj.bjp.0705348
Sodium (2‐sulfonatoethyl) methanethiosulfonate prevents S‐nitroso‐L‐cysteine activation of Ca2+‐activated K+ (BKCa) channels in myocytes of the guinea‐pig taenia caeca
Authors: Lang Richard J , Harvey John R , Mulholland Emily L
Published: July 2003

The modulation of large conductance Ca2+‐activated K+ (BKCa) channels by the nitric oxide (NO·) donor, S‐nitroso‐L‐cysteine (NOCys) and three sulfhydryl‐specific methanethiosulfonate (MTS) reagents, positively charged 2‐aminoethyl MTS hydrobromide (MTSEA C3H9NO2S2HBr) and [2‐(trimethylammonium) ethyl MTS bromide (MTSET C6H16NO2S2Br), and negatively charged sodium (2‐sulfonatoethyl) MTS (MTSES C3H7O5S3Na) were compared in excised inside‐out membrane patches of the guinea‐pig taenia caeca.

In membrane patches bathed in a low Ca2+ (15 nM) high K+ physiological salt solution, 1–3 BKCa channels opened with a low probability (N.Po) of 0.019±0.011 at 0 mV. N.Po readily increased with membrane depolarization, raised Ca2+ concentration or upon the addition of NOCys (10 μM for 2–5 min) such that 5–15 open BKCa channels were evident.

MTSEA (2.5 mM) decreased, while MTSES (2.5 mM) increased N.Po (at 0 mV) and the number of open BKCa channels at positive potentials. These changes in channel activity remained after a prolonged washout of these two MTS reagents.

MTSET (2.5 mM) increased N.Po (at 0 mV) and voltage‐dependently decreased BKCa current amplitudes in a manner readily reversed upon washout.

Pre‐exposure of excised membrane patches to MTSES or N‐ethylmaleimide (NEM 1 mM), a specific alkylating agent of cysteine sulfhydryls, but not MTSEA or MTSET, prevented the excitatory actions of NOCys (10 μM).

It was concluded that NOCys‐evoked increases in BKCa channel activity occur via the S‐nitrosylation of cysteine residues within basic regions of the channel α subunit that have an accessible water interface.

British Journal of Pharmacology (2003) 139, 1153–1163. doi:10.1038/sj.bjp.0705349
Adrenomedullin upregulates M2‐muscarinic receptors in cardiomyocytes from P19 cell line
Authors: Buys Sophie , Smih Fatima , Pathak Atul , Philip‐Couderc Pierre , Verwaerde Patrick , Montastruc Jean‐Louis , Rouet Philippe , Senard Jean‐Michel
Published: July 2003

The effects of AM on expression of muscarinic (M) receptors from P19‐derived cardiomyocytes were examined.

RT–PCR experiments revealed expression of M1–M4 receptor genes. Immuno‐histochemistry indicated that M2 expression is restricted to contractile cells. Carbachol inhibition of isoprenaline‐induced increase in beating rate was prevented by atropine and methoctramine (pA2: 8.1). Inhibition of [3H]‐NMS binding by atropine (pKi: −8.4±0.2) and methoctramine (pKi: −8.3±0.2) suggests that M2 is the functional expressed isoform.

[3H]‐NMS binding and semiquantitative RT–PCR studies showed a dome shaped time course of M2 expression with a maximum at 7 days of differentiation followed by a progressive decline.

AM concentration‐dependently upregulated M2 receptor mRNA during late differentiation stages in P19 cells but also in rat atrial cardiomyocytes. This effect was potentiated by factor H. AM (100 nM) plus factor H (50 nM) treatment of P19 cells for 24 h significantly increased [3H]‐NMS‐specific binding (Bmax: 81±7 vs 31±6 fmol mg−1 prot). The effect of AM on mRNA levels was prevented by AM receptor antagonist AM22–52 (1 μM) but not by CGRP antagonist, CGRP8–37 (1 μM).

The mRNA levels encoding CRLR receptor declined with culture duration, whereas those encoding L1/G10D receptor remained stable.

Our findings demonstrate that AM regulates M2 receptors expression in cardiomyocytes probably through a mechanism involving L1/G10D receptors. The ‘in vivo’ significance of this phenomenon remains to be demonstrated.

British Journal of Pharmacology (2003) 139, 1219–1227. doi:10.1038/sj.bjp.0705350
Comparative regional haemodynamic effects of the nitric oxide synthase inhibitors, S‐methyl‐L‐thiocitrulline and L‐NAME, in conscious rats
Authors: Wakefield Ian D , March Julie E , Kemp Philip A , Valentin Jean‐Pierre , Bennett Terence , Gardiner Sheila M
Published: July 2003

The regional haemodynamic effects of the putative nNOS inhibitor, S‐methyl‐L‐thiocitrulline (SMTC), were compared with those of the nonselective NOS inhibitor, NG‐nitro‐L‐arginine methyl ester (L‐NAME), in conscious, male Sprague–Dawley rats.

SMTC (0.3 mg kg−1 bolus) produced a significant, short‐lived, pressor effect associated with renal, mesenteric and hindquarters vasoconstriction; the same dose of L‐NAME did not affect mean blood pressure (BP), although it caused bradycardia and mesenteric vasoconstriction.

At the highest dose tested (10 mg kg−1), L‐NAME produced a significantly greater bradycardia and fall in mesenteric vascular conductance than SMTC, although the initial pressor response to SMTC was greater, but less sustained, than that to L‐NAME.

Infusion of SMTC or L‐NAME (3 mg kg−1 h−1) induced rises in BP and falls in renal, mesenteric and hindquarters vascular conductances, but the effects of L‐NAME were greater than those of SMTC, and L‐NAME also caused bradycardia.

The renal vasodilator response to acetylcholine was markedly attenuated by infusion of L‐NAME, but unaffected by SMTC. The hindquarters vasodilatation induced by salbutamol was attenuated by L‐NAME, but not by SMTC. The mesenteric vasodilator response to bradykinin was modestly enhanced by SMTC, but not by L‐NAME. The depressor and renal, mesenteric and hindquarters vasodilator responses to sodium nitroprusside were enhanced by L‐NAME, whereas SMTC modestly enhanced the hypotensive and renal vasodilator effects of sodium nitroprusside, but attenuated the accompanying tachycardia.

The results are consistent with the cardiovascular effects of low doses of SMTC being attributable to nNOS inhibition.

British Journal of Pharmacology (2003) 139, 1235–1243. doi:10.1038/sj.bjp.0705351
The Yin/Yang of superoxide dismutase mimetics: potential cardiovascular therapies?
Authors: Weber David S , Griendling Kathy K
Published: July 2003

British Journal of Pharmacology (2003) 139, 1059–1060. doi:10.1038/sj.bjp.0705353
Superoxide dismutase mimetic M40403 improves endothelial function in apolipoprotein(E)‐deficient mice
Authors: Jiang Fan , Guo Yanan , Salvemini Daniela , Dusting Gregory J
Published: July 2003

Overproduction of superoxide anions in the vascular wall contributes to endothelial dysfunction in vascular disease. A superoxide‐generating reduced β‐nicotinamide adenine dinucleotide phosphate (NADPH) oxidase has recently been identified as a major source of oxidative radicals in vascular tissues. We studied the effects of a synthetic manganese‐containing superoxide dismutase (SOD) mimetic, M40403, on NADPH oxidase‐dependent superoxide generation and on endothelial dysfunction.

In rat aortic smooth muscle cells, NADPH (100 μM) markedly stimulated superoxide production as detected by lucigenin (5 μM)‐enhanced chemiluminescence. M40403 reduced NADPH oxidase‐dependent superoxide production in a concentration‐dependent manner, with IC50 being 31.6 μM. In contrast, native Cu/Zn SOD (up to 300 U ml−1) had no effect. Angiotensin II (100 nM) increased the NADPH oxidase activity by 70%, and treatment with M40403 (10 μM) reduced this increased superoxide to the control level.

In aortae from apolipoprotein(E)‐deficient mice (apoE0) with hyperlipidemia and atherosclerosis, superoxide production is largely derived from NADPH oxidase. The attenuation of endothelial nitric oxide vasodilator function parallels the increase in vascular superoxide production at different stages of the disease. Acute incubation of such aortic rings with M40403 significantly suppressed superoxide production and improved endothelium‐dependent vasorelaxation to a level comparable to that in wildtype control mice.

In summary, the cell‐permeable SOD mimetic M40403 was found to reverse endothelial dysfunction in apoE0 aorta ex vivo by decreasing NADPH oxidase‐dependent superoxide levels. The advantages of synthetic SOD mimetics over the native Cu/Zn SOD enzyme, such as greater cell permeability and stability, confer significant therapeutic potential in vascular disease.

British Journal of Pharmacology (2003) 139, 1127–1134. doi:10.1038/sj.bjp.0705354
Role of endogenous adenosine in the acute and late response to allergen challenge in actively sensitized Brown Norway rats
Authors: Ellis K M , Mazzoni L , Fozard J R
Published: July 2003

Endogenous adenosine has been suggested to amplify the response of airway mast cells to allergen in vivo. We have sought evidence for this by monitoring the acute and late‐phase response to allergen in Brown Norway (BN) rats actively sensitised to ovalbumin (OA) and treated either with adenosine deaminase (ADA) linked covalently to polyethylene glycol (PEG‐ADA; Adagen®) to decrease adenosine availability or with erythro‐9‐(2‐hydroxy‐3‐nonyl)adenine (EHNA), an inhibitor of ADA, plus S‐(4‐nitrobenzyl)‐6‐thioinosine (NBTI), an inhibitor of facilitated adenosine transport, to increase adenosine availability.

The cardiovascular effects of adenosine (0.01–3 mg kg−1 i.v.) were significantly reduced in PEG‐ADA‐treated animals and augmented in EHNA/NBTI‐treated animals. The difference in sensitivity to adenosine in the treated groups was 33‐ and 15‐fold, at the level of 30% reduction in blood pressure and heart rate, respectively.

The acute response to allergen, given either intravenously or intratracheally, was quantified as bronchoconstriction. The late phase to allergen was measured as the influx and activation of immunoinflammatory cells into the bronchoalveolar lavage fluid 24 h after challenge.

Despite evidence of a substantial difference in adenosine availability following pretreatment with PEG‐ADA or EHNA/NBTI, there were no differences in either the acute or late response to allergen in the actively sensitised BN rat.

Our data suggest no role for endogenous adenosine in determining the response to allergen under our experimental conditions.

British Journal of Pharmacology (2003) 139, 1212–1218. doi:10.1038/sj.bjp.0705355
Antidepressant fluoxetine enhances glucocorticoid receptor function in vitro by modulating membrane steroid transporters
Authors: Pariante Carmine M , Kim Richard B , Makoff Andrew , Kerwin Robert W
Published: July 2003

Incubation of LMCAT fibroblast cells with antidepressants potentiates glucocorticoid receptor (GR)‐mediated gene transcription in the presence of dexamethasone and cortisol, but not of corticosterone. We have shown that antidepressants do so by inhibiting the LMCAT cell membrane steroid transporter (which is virtually identical to the multidrug resistance P‐glycoprotein) and thus by increasing dexamethasone or cortisol intracellular concentrations. However, previous experiments with the antidepressant fluoxetine in the presence of dexamethasone have produced negative results (Pariante et al. (2001). Br. J. Pharmacol., 134, 1335–1343).

We have since re‐examined the effects of fluoxetine on GR‐mediated gene transcription in the presence of dexamethasone. Moreover, we have examined the effects of fluoxetine on GR‐mediated gene transcription in the presence of cortisol and corticosterone, and on the intracellular accumulation of radioactive cortisol and corticosterone. Finally, we have examined the effects of fluoxetine on inhibition of P‐glycoprotein activity in Caco‐2 cells.

We now find that fluoxetine (1–10 μM) enhances GR‐mediated gene transcription in the presence of dexamethasone and cortisol (+140–170%), but not of corticosterone, and increases the intracellular accumulation of 3H‐cortisol (+5–15%), but not of 3H‐corticosterone. Moreover, fluoxetine (10 μM) induces approximately 30% inhibition of PGP activity in Caco‐2 cells.

Our results show that fluoxetine, like other antidepressants, inhibits membrane steroid transporters.

British Journal of Pharmacology (2003) 139, 1111–1118. doi:10.1038/sj.bjp.0705357