Jean-Michel Mencia-Huerta

Effect of endothelin-1 on blood pressure and bronchopulmonary system of the guinea pig.

Summary The bronchopulmonary and pressor effects of endothelin-1 (ET-1), a newly described vasoconstrictor peptide produced by endothelial cells, were investigated in the guinea pig. Intravenous injection of ET-1 (1 nmol/kg) induced an increase in pulmonary inflation pressure (PIP) as well as an important and sustained increase in arterial blood pressure (BP). Pretreatment of these animals with propranolol (1 mg/kg i.v.), provoked a significant enhancement of the ET-1-induced increase in PIP, accompanied by a dramatic and significant decrease of BP. When administered by aerosol for 1 min, ET-1 (1, 5, or 10

Bronchial hyperresponsiveness and cellular infiltration in the lung of guinea-pigs sensitized and challenged by aerosol

mUg/ml) induced a dose-dependent increase in PIP that was maximal by 4–5 min, but no significant change of BP. Pretreatment of guinea pigs with propranolol (1 mg/kg), mepyramine (1mg/kg i.v.), nifedipine (50 mg/kg i.p.), or verapamil (0.3 mg/kg i.v.) did not inhibit the bronchopulmonary response evoked by aerosol administration of 10

Regulation of IgE production from human mononuclear cells by β2‐adrenoceptor agonists

mUg/ml of ET-1. In contrast, pretreatment of the animals with indomethacin (10 mg/kg i.v.) or BN 52021 (10 mg/kg i.v.) significantly reduced the bronchopulmonary response of ET-1 given by aerosol. Injection of ET-1 (0.1, 0.3, and 1

Activation of guinea pig alveolar macrophages by endothelin-1

mUg) into isolated guinea pig lungs caused significant increases in PIP that were accompanied by the release of T

Endothelin-1 and bronchial hyperresponsiveness in the guinea pig

B2 but not histamine. These results demonstrate that ET-1 induces bronchopulmonary alterations in the guinea pig that appear to be dissociated from the systemic vascular effects of the peptide.

Phosphoramidon potentiates the endothelin-1-induced bronchopulmonary response in guinea-pigs.

We have studied the development of airway hyperresponsiveness and the pulmonary cell infiltration in a guinea‐pig model in which both initial sensitization and subsequent exposure to the antigen were performed by aerosol. Enhanced bronchopulmonary response to aerosol administration of acetylcholine (ACh) and 5‐hydroxytryptamine (5‐HT) was observed 3–4 hr and 18–24 hr after antigen exposure of sensitized animals. In contrast, when ACh and 5‐HT were administered intravenously 3–4 hr after the challenge, no significant alteration of the dose ‐response curves was observed. However, 18–24 hr after antigen challenge, a marked leftward shift of the dose‐response curve was observed on intravenous injection of ACh or 5‐HT. The increased bronchial reactivity to aerosoli?.ed ACh in sensitized and challenged guinea‐pigs reached a maximum by days 2–4, was still significantly increased at day 5 and returned to the basal value by day 8. No further alteration of the dose‐related bronchopulmonary response to aerosol or intravenous administration of ACh was recorded 24 hr after a second antigen challenge, performed 8 days after the initial one. The analysis of bronchoalveolar lavage fluids showed a significant increase in the number of polymorphonuclear neutrophils 3–4 hr after the exposure of sensitized animals to the antigen, which was also associated with a significant eosinophilia at 18–24 hr. Histological examination of lung specimens obtained from animals 3–4 hr following challenge demonstrated eosinophil infiltration in the peribronchial regions and bronchial walls, as well as within the epithelium. Furthermore, as compared to time 3–4 hr, less eosinophils in the peribronchial area and submucosa were counted 24 hr after antigen challenge. However, a role of eosinophil‐derived products in the development of bronchial hyperresponsivenss in this experimental model remains to be established.

Purification of normal human bone-marrow-derived basophils.

The present study examined the effect of β2‐adrenoceptor agonists on the interleukin‐4 (IL‐4)‐driven IgE production and on the possible mechanisms of action of these compounds. We present evidence that salbutamol and fenoterol potentiated the IL‐4‐induced IgE production by human peripheral blood mononuclear cells (PBMC). No significant effect of incubation in the presence of β2‐adrenoceptor agonists on IgG, IgA and IgM production was observed. Salbutamol and fenoterol inhibited interferon‐(IFN)‐γ production by PHA‐activated human PBMC suggesting that the blockade of the production of this cytokine could possibly explain the enhancement of IgE production. Salbutamol and fenoterol potentiated the IL‐4‐induced production of sCD23 whereas no effect on CD23 expression was observed. The potentiating effect of salbutamol on IgE production was blocked by two antagonists of β2‐adrenoceptor, namely butoxamine and D,L‐propranolol, suggesting a β‐adrenoceptor‐mediated event. These results demonstrate that β2‐adrenoceptor stimulation results in an increase in IgE production by human B lymphocytes.

Effect of Limonene and Sobrerol on Monocrotaline-lnduced Lung Alterations and Pulmonary Hypertension

Endothelin-1 (ET-1) induced a concentration- and time-dependent increase in arachidonic acid release from guinea pig alveolar macrophages, a maximum being reached at 1 nM ET-1. Regarding the time-course study, maximal release of arachidonic acid was observed after 30 s of incubation with ET-1 and then followed by a marked decrease, suggesting a reuptake of free arachidonic acid. ET-1 (0.1-10 nM) induced a concentration- and time-dependent release of TXB2, the stable metabolite of TXA2, evaluated by an ELISA technique. Maximum release was also obtained with 1 nM ET-1 but only after a 1-min incubation period. By contrast, ET-1 (1 pM-1 microM) did not stimulate the release of superoxide anion at any time point of the kinetic study. These results suggests that ET-1 may activate guinea pig alveolar macrophages, probably through a mechanism involving the arachidonic acid pathway.

Modulation of IgE Production in the Mouse by β2-Adrenoceptor Agonist

Human basophils activated through high‐affinity immunoglobulin E (IgE) receptors (FcRI) are involved in the late phase of the allergic reaction. To investigate the possible involvement of protein‐tyrosine kinases in this activation we used human acute basophilic leukemia (ABL) cells in culture as well as a pure population of normal basophils in vitro‐derived from human bone marrow precursor cells (HBMB). ABL cells were 50–80% basophils at various stages of maturation as assessed by staining, morphology, ultrastructure, and flow cytometry analysis, and only basophils in ABL cells expressed FcRI. Aggregation of FcRI by IgE and anti‐IgE, IgE and antigen, or anti‐FcRI monoclonal antibodies on ABL cells or on HBMB, led to increased tyrosine phosphorylation of 120‐, 100‐, 80‐, 72‐, 50‐ to 65‐, and 38‐kDa substrates. Tyrosine phosphorylations in ABL cells were in basophils because 1) they were detected after a 5‐s stimulation, 2) they were observed under conditions where mediator release is minimal, i.e., in the absence of extracellular calcium, 3) hapten addition during antigen stimulation resulted in almost total disappearance of tyrosine phosphorylations within 30 s. There was correlation between histamine release and tyrosine phosphorylation in anti‐IgE dose‐responses and in dose‐responses of the tyrosine kinase inhibitor genistein. The tyrosine kinase p72 syk was detected in the cells. Stimulation of ABL cells for 1 min resulted in extracellular calcium‐independent tyrosine phosphorylation and activation of p72 syk Therefore, tyrosine kinases are involved in the early steps of human FcRI signaling in basophils. Tyrosine kinases and their substrates could represent new potential therapeutic targets to prevent the development of the allergic reaction. 1996.