Dependence of monocyte chemoattractant protein 1 induced hyperalgesia on the isolectin B4-binding protein versican.

The type 1 chemokine monocyte chemoattractant protein (MCP-1) has been implicated in the generation of inflammatory and neuropathic pain, but the underlying mechanism remains poorly understood. Here we show that mechanical hyperalgesia induced by intradermal injection of MCP-1 in the rat is blocked by the intrathecal administration of isolectin B4 (IB4)-saporin, a selective neurotoxin for IB4(+)/Ret(+)-nociceptors. MCP-1-induced hyperalgesia is also attenuated by intrathecal antisense oligodeoxynucleotides targeting mRNA for versican, a molecule that binds MCP-1 and that also renders the Ret-expressing nociceptors IB4-positive (+). Finally, peripheral administration of ADAMTS-4 or chondroitinase ABC, two enzymes that disrupt versican integrity by the degradation of the versican core-protein or its chondroitin sulfate glycosaminoglycan side chains, respectively, also attenuated MCP-1 hyperalgesia at the site of nociceptive testing. We suggest that versican's glycosaminoglycan side chains present MCP-1 to a CCR2 expressing cell type in the skin that, in turn, selectively activates IB4(+)/Ret(+) nociceptors, thereby contributing to enhanced mechanical sensitivity under inflammatory conditions.

Role of interleukin-6 in chronic muscle hyperalgesic priming.

After recovery from acute muscle pain even minor subsequent muscle use can initiate recurrence of the same mechanical hyperalgesia months or years after the initial injury. We have recently developed a model of this chronic latent hyperalgesia in the rat. In this study, we have examined the possibility that interleukin-6 (IL-6), an inflammatory mediator produced during acute muscle inflammation, can mediate the production of this chronic latent hyperalgesic state in which subsequent exposure to inflammatory mediators produces a markedly prolonged mechanical hyperalgesia. We now report that i.m. injection of IL-6 produced mechanical hyperalgesia, lasting several hours, that was prevented by intrathecal injection of antisense to glycoprotein 130 (gp130), an IL-6 receptor subunit. Furthermore, following complete recovery from i.m. IL-6-induced hyperalgesia, i.m. prostaglandin E(2) produced a mechanical hyperalgesia that was remarkably prolonged compared with naïve controls, indicating the presence of chronic latent hyperalgesia. This ability of IL-6 to produce chronic latent hyperalgesia was prevented by intrathecal administration of antisense for gp130. Furthermore, gp130 antisense also prevented chronic latent hyperalgesia produced by i.m. injection of the inflammogen, carrageenan. These results identify a role for IL-6 in acute inflammatory muscle pain and as a potential target against which therapies might be directed to treat chronic muscle pain.

Severity of alcohol-induced painful peripheral neuropathy in female rats: role of estrogen and protein kinase (A and Cepsilon).

Small-fiber painful peripheral neuropathy, a complication of chronic ethanol ingestion, is more severe in women. In the present study, we have replicated this clinical finding in the rat and evaluated for a role of estrogen and second messenger signaling pathways. The alcohol diet (6.5% ethanol volume:volume in Lieber-DeCarli formula) induced hyperalgesia with more rapid onset and severity in females. Following ovariectomy, alcohol failed to induce hyperalgesia in female rats, well past its time to onset in gonad intact males and females. Estrogen replacement reinstated alcohol neuropathy in the female rat. The protein kinase A (PKA) inhibitor (Walsh inhibitor peptide, WIPTIDE) only attenuated alcohol-induced hyperalgesia in female rats. Inhibitors of protein kinase Cepsilon (PKCepsilon-I) and extracellular-signal related kinase (ERK) 1/2 (2'-amino-3'-methoxyflavone (PD98059) and 1,4-diamino-2, 3-dicyano-1, 4-bis (2-aminophenylthio) butadiene (U0126)) attenuated hyperalgesia in males and females, however the degree of attenuation produced by PKCepsilon-I was much greater in females. In conclusion, estrogen plays an important role in the expression of pain associated with alcohol neuropathy in the female rat. In contrast to inflammatory hyperalgesia, in which only the contribution of PKCepsilon signaling is sexually dimorphic, in alcohol neuropathy PKA as well as PKCepsilon signaling is highly sexually dimorphic.

Key role for the epsilon isoform of protein kinase C in painful alcoholic neuropathy in the rat.

Chronic alcohol consumption produces a painful peripheral neuropathy for which there is no reliably successful therapy, attributable to, in great part, a lack of understanding of the underlying mechanisms. We tested the hypothesis that neuropathic pain associated with chronic alcohol consumption is a result of abnormal peripheral nociceptor function. In rats maintained on a diet to simulate chronic alcohol consumption in humans, mechanical hyperalgesia was present by the fourth week and maximal at 10 weeks. Thermal hyperalgesia and mechanical allodynia were also present. Mechanical threshold of C-fibers in ethanol fed rats was lowered, and the number of action potentials during sustained stimulation increased. The hyperalgesia was acutely attenuated by intradermal injection of nonselective protein kinase C (PKC) or selective PKCepsilon inhibitors injected at the site of nociceptive testing. Western immunoblot analysis indicated a higher level of PKCepsilon in dorsal root ganglia from alcohol-fed rats, supporting a role for enhanced PKCepsilon second-messenger signaling in nociceptors contributing to alcohol-induced hyperalgesia.

Role of protein kinase Cepsilon and protein kinase A in a model of paclitaxel-induced painful peripheral neuropathy in the rat.

The clinical use of the antineoplastic agent paclitaxel (Taxol) is significantly limited in its effectiveness by a dose-related painful peripheral neuropathy. To evaluate underlying mechanisms, we developed a model of Taxol-induced painful peripheral neuropathy in the rat and determined the involvement of two second messengers that contribute to enhanced nociception in other models of inflammatory and neuropathic pain, protein kinase Cepsilon and protein kinase A. Taxol administered acutely, or chronically over 12 days, produced a decrease in mechanical nociceptive threshold. Acutely, Taxol induced hyperalgesia that was significant within 1 h, maximal after 6 h and resolved completely by 24 h after a single treatment. Chronically, Taxol treatment resulted in a dose (0.1-1 mg/kg/day)-dependent decrease in nociceptive threshold, measured 24 h after administration, maximal within 5 days from the commencement of Taxol administration and resolving by 2 weeks after the last dose of Taxol. Chronic Taxol treatment also increased the number of action potentials evoked by sustained (60-s) threshold and suprathreshold (10-g) stimulation of a sub-population of C-fibers in rats with Taxol-induced hyperalgesia. Mechanical allodynia and thermal hyperalgesia were also present in Taxol-treated rats. Hyperalgesia, produced by both acute and chronic Taxol, was attenuated by intradermal injection of selective second messenger antagonists for protein kinase Cepsilon and protein kinase A. These findings provide insight into the mechanism of Taxol-induced painful peripheral neuropathy that may help control side effects of chemotherapy and improve its clinical efficacy.

[Fluorometric method of determining prolylendopeptidase activity in human erythrocytes in normal and pathologic conditions]. / Fluorometricheskii metod opredeleniia aktivnosti proliléndopeptidaz v éritrotsitakh liudei v norme i pri patologicheskikh sostoianiiakh.

A highly sensitive fluorometric method for determination of prolylendopeptidase (PE) activity in human erythrocyte hemolysates in the presence of hemoglobin has been developed. The method is based on measurement of fluorescence of 4-methyl-7-aminocoumarine released in the course of enzymatic reaction from the substrate Z-glycyl-proline-4-methylcoumarine-7-amide. A correlation was introduced for the quenching of fluorescence by hemoglobin. The method is suitable for the determination of PE activity in human erythrocyte hemolysates in various pathological states. The dependence of PE activity on the incubation time, protein and substrate concentrations were studied using the 1,200-fold purified preparations of prolylendopeptidase II. The values of PE activity in erythrocyte hemolysates of healthy donors and in those of patients with odontogenic phlegmons of maxillary-facial area were virtually identical. PE activity in erythrocyte hemolysates of stored blood was 5 times lower than that in the cell hydrolysates of fresh blood. The PE activity was not observed in blood serum of fresh and stored blood of healthy persons and of patients with acute inflammatory processes of maxillary-facial area, as well as in blood serum of patients with hepatitis and glomerulopephritis.

[A comparative study of the effectiveness of 5% human albumin and 10% hydroxyethyl starch (HAES-steril) for correcting hemodynamics and O2 transport in surgical interventions]. / Sravnitel'noe issledovanie éffektivnosti primeneniia pri khirurgicheskikh vmeshatel'stvakh 5% chelovecheskogo al'bumina i 10% gidroksiétil-krakhmala (HAES-steril) po pokazateliam gemodinamiki i transporta O2.

Forty patients subjected to cavitary operations were examined. A high risk of hemodynamic disorders necessitated invasive monitoring; with this aim in view a catheter was inserted for measuring arterial pressure and the Swan-Ganz catheter for measuring the pressure in the pulmonary artery, in which helped monitor the hemodynamics and oxygen transport in the course of hypervolemic hemodilution. Plasma substitutes (one of two) were selected at random. After catheterization of the left radial artery and insertion of the Swan-Ganz catheter in the pulmonary artery through the internal right jugular vein the patients were infused either 5% human albumin or 10% hydroxyethyl starch in a dose of 125 ml every 5 min. The parameters of hemodynamics and oxygen transport were recorded after 500 ml of the solution was infused and the wedge pressure of 18 mm Hg attained. Both agents appreciably improved the mean arterial pressure, central nervous pressure, and wedge pressure. Cardiac index, left ventricular output, and stroke volume increased in both groups, and the pulmonary vascular resistance decreased. Both agents improved oxygen utilization and appreciably decreased hemoglobin level. The positive effect of hydroxyethyl starch on cardiac index, pulmonary vascular resistance, left ventricular output, and oxygen utilization was more expressed; moreover, a lesser dose of this drug was needed than of 5% human albumin (Behringwerke, Marburg, Germany). Loss of plasma caused by surgical intervention was better compensated for with synthetic colloid solutions, such as 10% HAES-steril (Fresinium, Oberurzel, Germany), provided that plasma protein level was at least 3-4 g/dl. The effect of 10% HAES-steril as regards the increase of circulating blood volume is 145%. Due to the hyperoncotic direction of its action it has a positive impact on the hemodynamics and oxygen transport and is needed in lower doses than other colloid solutions.

[Basic intensive care of ischemic cerebral stroke. Method of therapeutic hemodilution]. / Bazovaia intensivnaia terapiia ishemicheskogo tserebral'nogo insul'ta. Metod terapevticheskoi gemodiliutsii.

Ischemic cerebral stroke (ICS) ranks among the most frequent causes of disability. The incidence of untoward consequences of ICS can be decreased by early adequate use of intensive care methods restoring tissue oxygenation in the focus. The most important methods of intensive care of ICS are measures notably improving microcirculation and essentially decreasing subsequent incidence of disabling complications. The basic component of intensive care ensuring favorable results is therapeutic hemodilution making use of modern plasma substitutes--second-generation hydroxyethyl starch Infukoll HES 6 and 10% solutions. Currently used methods including use of dextran-based solutions cannot normalize microcirculation in ICS patients, particularly if used in long course. Prolonged infusions of dextran-based solutions inevitably increases plasma viscosity and impairs the hemostasis system. An essential increase of plasma viscosity involves the need in a complex of appropriate drug therapy aimed at compensation for untoward aftereffects of high dextran doses. Therapeutic doses of dextran-based solutions do not notably improve blood rheology. By contrast, therapeutic hemodilution with Infukoll HES notably improves the results of intensive care of ICS.

[Infusion-transfusion therapy of acute blood loss during early surgeries in children with severe thermal trauma]. / Infuzionno-transfuzionnaia terapiia ostroi krovopoteri vo vremia rannikh operatsii u detei s tiazheloi termicheskoi travmoi.

Research results of the central hemodynamics, microcirculation and of oxygen status are described for 48 children (aged 8 months to 14 years) as observed during surgeries aggravated by massive hemorrhage in the routine infusion-transfusion therapy plus a 6% solution of INFUKOL GEK. Solution dosages of 6% were approved; the drug's positive effect on the central-hemodynamics condition, microcirculation and on the oxygen regime, as observed in the process of the infusion therapy made to compensate for a massive blood loss, was demonstrated; besides, the related shrinking of the infusion therapy total volume and the possibility to give up totally or to significantly reduce the blood-drug preparations, administered intraoperatively, were shown.

Activation of Gi induces mechanical hyperalgesia poststress or inflammation.

In studies of the role of primary afferent nociceptor plasticity in the transition from acute to chronic pain we recently reported that exposure to unpredictable sound stress or a prior inflammatory response induces long-term changes in the second messenger signaling pathway, in nociceptors, mediating inflammatory hyperalgesia; this change involves a switch from a G(s)-cAMP-PKA to a G(i)-PKCepsilon signaling pathway. To more directly study the role of G(i) in mechanical hyperalgesia we evaluated the nociceptive effect of the G(i) activator, mastoparan. Intradermal injection of mastoparan in the rat hind paw induces dose-dependent (0.1 ng-1 microg) mechanical hyperalgesia. The highly selective inhibitors of G(i), pertussis toxin, and of protein kinase C epsilon (PKCepsilon), PKCepsilonV(1-2), both markedly attenuate mastoparan-induced hyperalgesia in stressed rats but had no effect on mastoparan-induced hyperalgesia in unstressed rats. Similar effects were observed, at the site of nociceptive testing, after recovery from carrageenan-induced inflammation. These studies provide further confirmation for a switch to a G(i)-activated and PKCepsilon-dependent signaling pathway in primary mechanical hyperalgesia, induced by stress or inflammation.

Some considerations on veterinary drug use and supply in Nigeria.

There is widespread misuse of veterinary drugs in Nigeria resulting from controlled and unsupervised drug administration, underdosing and incomplete treatment. Development of resistance and toxicity are common consequences of this misuse. Drug shortage, uneven distribution, preponderance of fake and/or expired drugs and inadequate local drug production are some of the problems identified in veterinary drug supply. All these problems have an adverse effect on animal health and productivity and are related to an improperly coordinated veterinary service and the non-existence of national veterinary drug policy. Suggested solutions include rehabilitation and restructuring of the veterinary service, improved funding to support drug purchase, installation of self-servicing revolving funds, partial privatization, drug manufacture and appropriate legislations for veterinary drugs. These proposals are expected to overcome bottlenecks encountered in drug supply, distribution, delivery, prescription and use. Projections and plans must also be made toward the local development and manufacture of drugs for animal disease.

Sex hormones regulate the contribution of PKCepsilon and PKA signalling in inflammatory pain in the rat.

We have evaluated the contribution of differences in second messenger signalling to sex differences in inflammatory pain and its control by sex hormones. In normal male but not female rats, epinephrine-induced mechanical hyperalgesia was antagonized by inhibitors of protein kinase Cepsilon (PKCepsilon), protein kinase A (PKA) and nitric oxide synthetase (NOS). Similarly, in PKCepsilon knockout mice, a contribution of PKCepsilon to epinephrine-dependent mechanical hyperalgesia occurred in males only. In contrast, hyperalgesia induced by prostaglandin E2, in both females and males, was dependent on PKA and NO. In both sexes, inhibitors of mitogen-activated protein kinase/extracellular-signal related kinase kinase (MEK) inhibited epinephrine hyperalgesia. In gonadectomized females, the second messenger contributions to epinephrine hyperalgesia demonstrated the pattern seen in males. Administration of oestrogen to gonadectomized females fully reconstituted the phenotype of the normal female. These data demonstrate gender differences in PKCepsilon, PKA and NO signalling in epinephrine-induced hyperalgesia which are oestrogen dependent and appear to be exerted at the level of the beta-adrenergic receptor or the G-protein to which it is coupled.

[The effect of psychotropic substances on the deamination of monoamines in the rat brain]. / Vliianie psikhotropnykh veshchestv na dezaminirovanie monoaminov v mozge krysy.

A comparative study of antimonoamine oxidase activity of psychotropic agents of different classes was made. Phenothiazine, butyrophenone and atypical neuroleptics were found to suppress deamination of 2-phenylethylamine in the brain. Tranquilizers of benzodiazepine structure appeared to be inactive with respect to monoamine oxidase (MAO) of the brain. Anticonvulsants (except difenin) weakly inhibit serotonin deamination and, on the contrary, difenin stimulates serotonin- and 2-phenylethylamine deamination. Antidepressants--MAO inhibitors--more actively reduce the rate of serotonin deamination, and tricyclic antidepressant desimipramine is similar to aminazine by its effect on MAO. Phenamine is a potent MAO inhibitor. The effect of cocaine is significantly less pronounced.

[Reaction of deamination of monoamines in the brain and heart of rats under the toxic action of hyperbaric oxygenation]. / Reaktsiia dezaminirovaniia monoaminov v mozge i serdtse krys pri toksicheskom deistvii giperbaricheskoi oksigenatsii.

Kinetic parameters of monoamine deamination processes in the rat brain and heart after hyperbaric oxygenation (HBO) in toxic conditions (6 ata) were studied. HBO was shown to cause a substantial reduction in MAO affinity to serotonin in the brain, but not in the heart. Contrastingly, MAO affinity to dopamine was found to decrease in the heart, but not in the brain in response to HBO. Differences of tyramine and 2-phenylethylamine deamination in the rat brain and heart were also reciprocal following toxic HBO. In the initial phase of seizure episode MAO activity in the brain and heart was also different. Distinct mechanisms of adaptation to toxic oxygen in the central nervous system and cardiovascular system are discussed.

[Effect of benzamide derivatives on rat brain monoamine oxidase activity in vitro]. / Vliianie razlichnykh proizvodnykh benzamida na aktivnost' monaminoksidazy mozga krysy in vitro.

The ability of moclobamide and other benzamide derivatives to inhibit the activity of monoamine oxidase in the rat brain was studied. Distinct effects of these compounds on the deamination of serotonin and norepinephrine (MAO-A substrates); 2-phenylethylamine (selective MAO-B substrate); tyramine and dopamine (MAO-A and MAO-B substrates) are shown. It was demonstrated that among all the compounds studied moclobamide appeared to be the most active and selective inhibitor of MAO-A: at a concentration of 100 microM it caused a 100% inhibition of serotonin and norepinephrine deamination, which might be explained by the presence of C1 atom in the para-position of benzene ring in moclobamide molecule. Other benzamide derivatives were less active in inhibiting MAO-A and had but a negligible effect on dopamine- and 2-phenylethylamine deamination.

[Effect of benzamide derivatives on convulsions induced by the toxic action of oxygen in rats]. / Vliianie proizvodnykh benzamida na sudorogi, vyzvannye toksicheskim deistviem kisloroda u krys.

The reversible MAO-A inhibitor moclobemide (5 mg/kg) was shown to prevent seizures in rats during exposure to toxic oxygen (6 ata). Benzamide derivatives increased the latent period of oxygen seizures and decreased the lethality following hyperbaric oxygenation. The range of anti-MAO activity of moclobemide and clorgyline in the rat brain and heart after toxic oxygenation was studied. It was distinct from those in control animals. Clorgyline was found to be more active in inhibiting MAO during toxic oxygenation in the heart and moclobemide-in the brain. The possibility is shown to prevent oxygen seizures not only with irreversible MAO-A inhibitors (clorgyline), but also with reversible ones (moclobemide).

[Changes in the balance of biogenic monoamines and their metabolites in the organs of rats with oxygen-induced epilepsy]. / Izmenenie balansa biogennykh monoaminov i ikh metabolitov v organakh krys pri kislorodnoi épilepsii.

The content of some biogenic monoamines and their metabolites in rat brain and heart in different periods of oxygen epilepsia was studied using high performance liquid chromatography with electrochemical detection. It was shown that already at the 5th minute of exposure to oxygen adrenaline, DOPA and some noradrenaline metabolites disappeared in the brain and noradrenaline level reduced. At this period in rat heart the reduction of catecholamine content was the most distinct and serotonin level was unchanged. At the beginning of convulsive period the modifications of biogenic amines content were nonparallel in brain regions: in the heart the reduction of catecholamine level went on, especially in right ventricle. In the terminal phase of oxygen epilepsia brain biogenic amines increased, however, not up to normal meaning, heart catecholamines at this period were at the same level as at the beginning of the convulsive period.

[Kinetics of the oxidative deamination reaction in the preconvulsive period of oxygen-induced epilepsy]. / Kinetika reaktsii okislitel'nogo dezaminirovaniia v dosudorozhnom periode kislorodnoi épilepsii.

Kinetic parameters of monoamine oxidative deamination in compensatory and preconvulsive periods of oxygen epilepsia were studied. It was shown that in rat brain MAO's affinity for serotonin reduced from the 5th minute of exposure to hyperbaric oxygen and went on reducing on the 15th minute. In rat heart the affinity of MAO for serotonin firstly decreased and then returned to normal meaning. Dopamine deamination in rat brain in compensatory period of epilepsia was activated and then was inhibited. In rat heart from the 5th minute of exposure to oxygen dopamine and 2-phenylethylamine deamination was blocked. Tyramine deamination in preconvulsive period of epilepsia changed in a complex manner. It is concluded that the kinetic parameters of monoamine deamination change in the initial phases of exposure to hyperbaric oxygen, and the most distinct modifications take place in rat heart, but not in rat brain.

[The action of befol and its derivatives on monoamine oxidase of different origins]. / Deistvie befola i ego proizvodnykh na monoaminoksidazu razlichnogo proiskhozhdeniia.

The effect on deamination of serotonine, dopamine, tiramine and 2-phenylamine of benzamide derivatives befol, moclobemide and LIS-641 was studied. Befol and moclobemide are inhibitors of serotonine deaminating activity of MAO. The different sensitivity of this activity to the effect of the benzamide derivatives in beef or rat brain and human placenta was noted. The inhibition was more distinct in tissue homogenate than in corresponding mitochondrial fractions.