E.K. Hamasato

Amphetamine modulates cellular recruitment and airway reactivity in a rat model of allergic lung inflammation.

Asthma is characterized by pulmonary cellular infiltration, vascular exudation and airway hyperresponsiveness. Several drugs that modify central nervous system (CNS) activity can modulate the course of asthma. Amphetamine (AMPH) is a highly abused drug that presents potent stimulating effects on the CNS and has been shown to induce behavioral, biochemical and immunological effects. The purpose of this study was to investigate the effects of AMPH on pulmonary cellular influx, vascular permeability and airway reactivity. AMPH effects on adhesion molecule expression, IL-10 and IL-4 release and mast cell degranulation were also studied. Male Wistar rats were sensitized with ovalbumin (OVA) plus alum via subcutaneous injection. One week later, the rats received another injection of OVA-alum (booster). Two weeks after this booster, the rats were subjected to AMPH treatment 12 h prior to the OVA airway challenge. In rats treated with AMPH, the OVA challenge reduced cell recruitment into the lung, the vascular permeability and the cellular expression of ICAM-1 and Mac-1. Additionally, elevated levels of IL-10 and IL-4 were found in samples of lung explants from allergic rats. AMPH treatment, in comparison, increased IL-10 levels but reduced those of IL-4 in the lung explants. Moreover, the tracheal responsiveness to methacholine (MCh), as well as to an in vitro OVA challenge, was reduced by AMPH treatment, and levels of PCA titers were not modified by the drug. Our findings suggest that single AMPH treatment down-regulates several parameters of lung inflammation, such as cellular migration, vascular permeability and tracheal responsiveness. These results also indicate that AMPH actions on allergic lung inflammation include endothelium-leukocyte interaction mechanisms, cytokine release and mast cell degranulation.

Effects of MK-801 and amphetamine treatments on allergic lung inflammatory response in mice

Glutamate acts as a neurotransmitter within the Central Nervous System (CNS) and modifies immune cell activity. In lymphocytes, NMDA glutamate receptors regulate intracellular calcium, the production of reactive oxygen species and cytokine synthesis. MK-801, a NMDA receptor open-channel blocker, inhibits calcium entry into mast cells, thereby preventing mast cell degranulation. Several lines of evidence have shown the involvement of NMDA glutamate receptors in amphetamine (AMPH)-induced effects. AMPH treatment has been reported to modify allergic lung inflammation. This study evaluated the effects of MK-801 (0.25mg/kg) and AMPH (2.0mg/kg), given alone or in combination, on allergic lung inflammation in mice and the possible involvement of NMDA receptors in this process. In OVA-sensitized and challenged mice, AMPH and MK-801 given alone decreased cellular migration into the lung, reduced IL-13 and IL10 levels in BAL supernatant, reduced ICAM-1 and L-selectin expression in granulocytes in the BAL and decreased mast cell degranulation. AMPH treatment also decreased IL-5 levels. When both drugs were administered, treatment with MK-801 reversed the decrease in the number of eosinophils and neutrophils induced by AMPH in the BAL of OVA-sensitized and challenged mice as well as the effects on the expression of L-selectin and ICAM-1 in granulocytes, the IL-10, IL-5 and IL-13 levels in BAL supernatants and increased mast cell degranulation. At the same time, treatment with MK-801, AMPH or with MK-801+AMPH increased corticosterone serum levels in allergic mice. These results are discussed in light of possible indirect effects of AMPH and MK-801 via endocrine outflow from the CNS (i.e., HPA-axis activity) to the periphery and/or as a consequence of the direct action of these drugs on immune cell activity, with emphasis given to mast cell participation in the allergic lung response of mice.

Long-term amphetamine treatment exacerbates inflammatory lung reaction while decreases airway hyper-responsiveness after allergic stimulus in rats.

Asthma is an allergic lung disease can be modulated by drugs that modify the activity of central nervous system (CNS) such as amphetamine (AMPH). AMPH is a highly abused drug that exerts potent effects on behavior and immunity. In this study we investigated the mechanism involved in the effects of long-term AMPH treatment on the increased magnitude of allergic lung response. We evaluated mast cells degranulation, cytokines release, airways responsiveness and, expression of adhesion molecules. Male Wistar rats were treated with AMPH or vehicle (PBS) for 21 days and sensitized with ovalbumin (OVA) one week after the first injection of vehicle or AMPH. Fourteen days after the sensitization, the rats were challenged with an OVA aerosol, and 24h later their parameters were analyzed. In allergic rats, the treatment with AMPH exacerbated the lung cell recruitment due increased expression of ICAM-1, PECAM-1 and Mac-1 in granulocytes and macrophages recovered from bronchoalveolar lavage. Elevated levels of IL-4, but decreased levels of IL-10 were also found in samples of lung explants after AMPH treatment. Conversely, the ex-vivo tracheal hyper-responsiveness to methacholine (MCh) was reduced by AMPH treatment, whereas the force contraction of tracheal segments due to in vitro antigen challenge remained unaltered. Our findings suggest that lung inflammation and airway hyper-responsiveness due to OVA challenge are under the distinct control of AMPH during long-term treatment. Our data strongly indicate that AMPH positively modulates allergic lung inflammation via the increase of ICAM-1, PECAM-1, Mac-1 and IL-4. AMPH also abrogates the release of the anti-inflammatory cytokine IL-10.

Beta-adrenergic antagonist prevents anxiety like behavior and natural killer cells migration to the spleen in a model of cohabitation with sick partners

Cohabitation for 11 days with two Ehrlich tumor bearing-mice: two mice from control group were treated with vehicle (experimental day 1) and the other mouse was kept undisturbed (companion of health partner). Between ED6 and ED11, CHP were treated with vehicle or propranolol. Two mice from experimental group were inoculated with Ehrlich tumor cells i.p. and the other was kept undisturbed (companion of sick partner). Between ED6 and ED11, CSP were treated with vehicle or propranolol. During psychological stress, catecholamines produced by the sympathetic nervous system (SNS) regulate the immune system and cohabitation for 11 days with two Ehrlich tumor bearing-mice induces psychological stress. Besides, the aversive effects in cohabitation with sick partners are related with the release of odor cues. After cohabitation with sick companions the open field test was used to measure behaviors characteristic of anxiety and indicated that the cohabitation increase in anxiety-like behavior was blocked by pre-treatment with the beta-adrenergic antagonist propranolol. Pre-treatment with the beta-adrenergic antagonist propranolol did not significantly alter corticosterone levels indicating no difference in activation of the hypothalamic-pituitary-adrenal (HPA) axis. Likewise propranolol pre-treatment abrogated the migration of natural killer (NK) cells to the spleen. Collectively, these data suggest that behavioral and immune changes in the model of cohabitation with sick partners occur through beta-adrenergic dependent signaling.

44. Cohabitation with a sick-cage mate exacerbates allergic lung inflammatory response in mice

The objective of this study was analyze the effects of cohabitation with sick partner on allergic lung inflammatory response in ovalbumin (OVA) sensitized and challenged mice. Pairs of mice were divided into control and experimental groups. Within each group, one mouse from each pairs was immunized with a solution containing (OVA). The remaining mouse from the experimental group was injected with Ehrlich tumor cells being designated as “companion of sick partner” (CSP); the remaining mouse of the control group was injected with PBS being designated as “companion of healthy partner” (CHP). CSP mice presented in relation to CHP mice: increased number of eosinophils and neutrophils in the BAL; increased IL-4 and IL-5 levels and decreased IL-10 and INF-γ in the BAL supernatant; increased IgG1-OVA and decrease IgG2a-OVA levels on peripheral blood; increased expression of L-selectin in the BAL granulocytes; decreased in vitro tracheal reactivity to metacholine; no changes on plasma corticosterone levels and increased levels of plasmatic noradrenaline. The results suggest that the exacerbation of the allergic lung inflammatory response in CSP mice is a consequence of the psychological stress induced by forced long-term cohabitation with sick the partner, a fact that might ultimately depend on the changes induced by catecholamines on Th1/Th2 balance, toward a Th2 cytokine profile and finally the recruitment and activation of eosinophils in the airways. FAPESP: 2012/03372-3; 2009/51886-3.