Beta-adrenoceptor blockade ameliorates the clinical course of experimental allergic encephalomyelitis and diminishes its aggravation in adrenalectomized rats

As glucocorticoids influence both catecholamine synthesis and adrenoceptor expression by immune cells, the current study was undertaken to distinguish their direct effects on the development of experimental allergic encephalomyelitis from those induced by alteration of catecholamine signaling. We examined the influence of 16-day-long beta-adrenoceptor blockade with propranolol (0.40 mg/100 g body weight/day, s.c.) beginning 3 days before immunization on the development of experimental allergic encephalomyelitis in adrenalectomized (7 days before immunization) and in non-operated male Dark Agouti rats. Adrenalectomy aggravated the clinical course of experimental allergic encephalomyelitis. In contrast, propranolol attenuated both the clinical signs of the disease and decreased the number of lesions in the spinal cord. Furthermore, propranolol prevented adrenalectomy-induced aggravation of the disease course without affecting mortality. We also found that the percentage of CD4(+)CD25(+) T lymphocytes (recently activated or regulatory cells) was increased in peripheral blood of experimental allergic encephalomyelitis rats over that in the corresponding non-immunized and bovine serum albumin immunized rats. However, the percentage of these cells was reduced in adrenalectomized and/or propranolol-treated experimental allergic encephalomyelitis rats compared to control experimental allergic encephalomyelitis rats. Our findings, coupled with the clinical course of the disease and the underlying pathomorphological changes, clearly suggest that differential mechanisms were responsible for the changes in the percentage of CD4(+)CD25(+) T lymphocytes in propranolol-treated adrenalectomized rats and only propranolol-treated rats with experimental allergic encephalomyelitis. Our results, when viewed globally, indicate that: i) beta-adrenoceptor-dependent mechanisms are involved in the immunopathogenesis of experimental allergic encephalomyelitis, ii) experimental allergic encephalomyelitis has a more severe course in adrenalectomized rats and iii) beta-adrenoceptor-mediated mechanisms operate in adrenalectomy-induced aggravation of the disease.

Strain differences and the role for HSP47 and HSP70 in adjuvant arthritis in rats

Because of high sequence homology between microbial and endogenous heat shock proteins (HSP), immunological cross-reactivity to microbial HSP has been suggested as a possible cause of the development of autoimmune diseases, such as rheumatoid arthritis. The present study aimed to determine a potential role of HSP47, a molecular chaperone involved in the synthesis and assembly of collagen molecules, and microbial HSP71 (mHSP71) in adjuvant arthritis (AA) in two rat strains: Dark Agouti (DA), susceptible to AA induction and Albino Oxford (AO), which is resistant to AA induction. Immunization with complete Freund's adjuvant (CFA) induced an increased expression of HSP47 in joints of DA rats, which exhibited severe clinical signs of AA at the time of disease peak, while this protein was not detectable in joints of AO rats. In contrast, no strain differences in HSP72 (rat analogue of mHSP71) expressions in joints were observed. The increased levels of anti-HSP47 antibodies were detected in sera of DA rats during the AA peak, while the immunization with CFA increased levels of anti-mHSP71 antibodies in sera of AO rats. HSP47 and mHSP71 reduced proliferation of draining inguinal lymph node cells (LNC) in resistant AO rat strain, leading to a hypothesis that both HSP participated in AA control. Finally, mHSP71 potentiated the apoptotic response of LNC in susceptible DA rat strain. In conclusion, our findings indicate involvement of HSP47 in the development of AA in the rat, and point out to the regulatory role for both HSP47 and mHSP71.

Behavior and severity of adjuvant arthritis in four rat strains

Previous research has suggested that behavioral traits of the histocompatible Lewis and Fischer strains of rats could be related to the difference in their susceptibility to adjuvant arthritis (AA). In the present study, the predictive value of behavioral markers in susceptibility to AA was investigated in nonhistocompatible inbred DA, Lewis, Albino Oxford (AO), and outbred Wistar strain. Behavioral profiles (open filed test and forced swim test) were determined prior to immunization with a single intradermal injection of complete Freund's adjuvant. Animals were daily scored for clinical signs of AA. The occurrence of certain behaviors and clinical indices of AA was significantly associated with strain membership. Discriminant analysis identified strain-related behavioral and illness profiles with very few overlaps among the phenotypes. Discriminant classification significantly exceeded the proportion of cases, which could have been correctly classified on the basis of chance. Open field behavior, in particular, exploration and grooming, differentiated among AA-susceptible and AA-resistant strains. Multiple regression analysis indicated that severity of AA (maximum clinical sign) can be predicted by the latency time and grooming behavior in the open field independently of strain membership. No clear distinction between AA-susceptible and AA-resistant strains was found with respect to forced swim test immobility. It was concluded that (a) strain-related genetic predisposition is important for the expression of certain behavioral traits and for susceptibility to AA and (b) open field behaviors, particularly grooming and latency, predict susceptibility to AA across different rat strains.

Modulation of humoral immune responses in the rat by centrally applied Met-Enk and opioid receptor antagonists: functional interactions of brain OP1, OP2 and OP3 receptors

We have previously demonstrated that central application of leucine-enkephalin (Leu-Enk) elicits potentiation and suppression of humoral immune responses through OP(1) (delta) and OP(2) (kappa) receptors, respectively. Interestingly, both effects were found to be additionally dependent on OP(3) (mu) receptor function. In the present study, we have further investigated whether opioid receptor interactions underlie the immunomodulatory effects of endogenous opioids as well as exogenously applied methionine-enkephalin (Met-Enk). For that purpose, the plaque-forming cell (PFC) response was determined in rats injected intracerebroventricularly (i.c.v.) with opioid receptor-selective antagonists and Met-Enk. Application of the OP(1) antagonist ICI 174864, but not naltrindole, resulted in suppression of the PFC response. In contrast, i.c.v. injection of the OP(2) selective antagonist nor-binaltorphimine (nor-BNI) significantly potentiated the PFC response. Both effects, presumably mediated by endogenous opioid peptides, were antagonized by the OP(3) receptor antagonist beta-funaltrexamine (beta-FNA) at a dose that was devoid of immunomodulatory activity. The immunopotentiation of the PFC response induced by Met-Enk was reversed by OP(1) receptor antagonists, naltrindole and ICI 174864, but not by beta-FNA or nor-BNI. On the basis of these and previous findings, it may be concluded that central OP(3) receptors are permissive for the central immunomodulatory action of endogenous opioid peptides and Leu-Enk. In contrast, the central immunoenhancing effect of Met-Enk appears to be mediated through OP(3)-independent OP(1) receptors.

Peripheral effects of methionine-enkephalin on inflammatory reactions and behavior in the rat

Methionine-enkephalin (Met-Enk) induces notable alterations in immune and central nervous system functions. The present study was conducted in order to compare peripheral and central effects of Met-Enk on nonspecific immunity, open field behavior and pain perception in the rat. The results showed that 0.2 mg/kg of Met-Enk given intraperitoneally (i.p.) increased concanavalin A (Con-A)-induced paw edema and enhanced basal and phorbol myristate acetate (PMA)-stimulated H(2)O(2) production of peritoneal macrophages. Met-Enk-induced immunopotentiation was antagonized by anti-Met-Enk antibodies (anti-Met-Enk-Ig) and quaternary naltrexone (qNtx). Met-Enk injected i.p. produced an increase of horizontal and vertical locomotor activity in the open field that was reversed by i. p. administration of anti-Met-Enk-Ig and qNtx. The dose of 0.2 mg/kg of Met-Enk applied i.p. did not affect the number of writhes in the test of analgesia. Intracerebroventricular (i.c.v.) injection of Met-Enk, given in a dose that was previously shown to be immunostimulatory, enhanced only basal H(2)O(2) production of peritoneal macrophages, and anti-Met-Enk-Ig antagonized this effect. Besides, i.c.v. treatment with anti-Met-Enk-Ig increased and decreased H(2)O(2) production of peritoneal macrophages under basal and stimulated conditions, respectively. Met-Enk and anti-Met-Enk-Ig injected i.c.v. did not influence activity in the open field and pain sensitivity. Thus, the i.c.v. dose of Met-Enk that was sufficient to modulate immune functions did not influence behavior. It may be concluded that Met-Enk modulated nonspecific immune responses and open field behavior by peripheral mechanisms.

Changes in immunological and neuronal conditions markedly altered antibody response to intracerebroventricularly injected ovalbumin in the rat

The serum antibody response to ovalbumin (OA) has been investigated following intracerebroventricular (i.c.v.) and intravenous administration of antigen in the rat, under altered neuronal and immunological conditions. I.c.v. administration of antigen was far more potent in eliciting humoral immune response. Central nervous system (CNS) immunization under the conditions of disrupted blood-brain barrier decreased anti-OA antibody production. Peripheral polyclonal stimulation with Bordetella pertussis increased production of specific antibodies to i.c.v. injected antigen, while complete Freund's adjuvant had no effect on the immune response. These results suggest that CNS compartmentalization of antigen may be critical for mounting strong antibody production, and that peripheral polyclonal stimulation of the immune system may markedly contribute to the overall intensity of the immune response.

Suppression of adjuvant arthritis by kappa-opioid receptor agonist: effect of route of administration and strain differences

It is well established that kappa-opioid receptor agonists exert antiinflammatory and antihyperalgesic effects during nonspecific inflammation as well as suppressive effects on the development of humoral and cell-mediated immune responses to foreign antigens. The aim of this study was to investigate the ability of the kappa-opioid receptor agonist MR 2034 to modulate adjuvant arthritis in the rat. In the first series of experiments, treatments of Wistar rats were performed using several routes of drug administration: intraperitoneal (ip), intracaudal (ic), intracerebroventricular (icv) and intraplantar (ipl). MR 2034 significantly suppressed joint swelling after ip and ic treatment, slightly reduced inflammation after ipl treatment, and did not produce any effect after icv treatment. In the second series of experiments, the suppressive effect of ip injected MR 2034 was investigated using Wistar, Dark August (DA) and Lewis rats. In Wistar rats, MR 2034 significantly decreased the incidence of adjuvant arthritis, and suppressed mean joint score and aggregate joint score. Similarly, in DA rats treated with MR 2034, mean arthritic score was significantly suppressed, but other clinical parameters were not affected. In Lewis rats, however, ip treatment with MR 2034 failed to produce any suppressive effect on joint disease and even potentiated the initial development of arthritis. These data suggest that immunosuppressive and antiinflammatory action of MR 2034 markedly depend on the route of drug administration and strain susceptibility to opioids.

Modulation of humoral immune response by central administration of leucine-enkephalin: effects of mu, delta and kappa opioid receptor antagonists

The effect of leucine-enkephalin (Leu-Enk) on primary humoral immune response was investigated following intracerebroventricular (i.c.v.) administration of the peptide in the rat. Leu-Enk stimulated plaque-forming cell (PFC) response in rats i.c.v. injected with 0.1 and 1 micrograms/kg, whereas does of 20 and 50 micrograms/kg exerted immunosuppressive effects. I.c.v. treatment of rats with delta opioid receptor antagonist ICI 174,864 and kappa opioid receptor antagonist nor-binaltorphimine (nor-BNI) blocked stimulation and suppression of PFC response induced by Leu-Enk, respectively. The mu opioid receptor antagonist beta-funaltrexamine (beta-FNA) reversed both immunomodulatory effects produced by Leu-Enk. Since beta-FNA alone had no effect on PFC response (unlike ICI 174,864 and nor-BNI), these data showed that central effects of Leu-Enk on PFC response were mediated by brain mu opioid receptors, and suggested a possible involvement of delta and kappa opioid receptors.

[Status of information technology in health care institutions of Serbia]

The basic purpose of this study was to analyse the condition of the information technology in the health care institutions of Serbia in 1994. and to compare the results with similar investigation from 1992. in order to determine the state of its development and progress. The instrument used for the collection of data was questionnaire with 24 questions which was distributed to all independent health care institutions in the Republic of Serbia (total 238). The response rate was 40.8 percent. Out of the number of responded health institutions, 86 percent of them own computers which are in use, almost duble the number of institutions which had and used this equipment in 1992. The great majority of institutions had one or two PCs. Organized units for medical information systems were formed in 27.2 percent of institutions. Each of them in average uses two application softwares, from which one is for billing and payroll accounting. The development of information system technology has improved in relation to 1992. and is, with certain suggestions and activities a good basis for designing of a unique health care information system in Republic of Serbia.

Effect of Met-enkephalin and opioid antagonists on rat macrophages

Effects of Met-enkephalin (Met-ENK) and opioid antagonists on H2O2 release by peritoneal macrophages from DA and AO rats were investigated. Met-ENK increased and decreased H2O2 production by macrophages of DA and AO rats, respectively. These effects were antagonized by low, but not high, concentrations of naloxone and ICI 174864. High concentrations of both antagonists directly modulated H2O2 release and retained the strain-related differences seen with Met-ENK. The results showed direct, strain- and dose-dependent, effects of Met-ENK, naloxone, and ICI 174864 on rat macrophage function.