Objective: The present study analyzed the effects of acute amphetamine (AMPH) treatment on immune-mediated lung inflammatory response in rats. Methods: There were four experiments. In the first and second experiments, rats were treated with AMPH (1 mg/kg) or 0.9% NaCl, and locomotor activity (experiment 1) and serum AMPH concentrations (experiment 2) were measured 1 or 12 h after treatment. In the third experiment, rats which were immunized with ovalbumin (OVA) were treated 14 days later with 0.9% NaCl or AMPH (1 mg/kg). Twelve hours after these treatments, all animals were submitted to challenge by 1% OVA inhalation being analyzed afterwards for bronchoalveolar lavage fluid (BAL), peripheral blood and bone marrow cellularity. In the fourth and final experiment, rats were treated and studied as for experiment 3, except that half of the animals within each group were previously treated with metyrapone prior to the OVA challenge. Results: In the non- immunized rats, AMPH treatment induced an increase in locomotor activity synchronized to high serum AMPH concentrations 1 h after, but not 12 h after treatment. In OVA-challenged rats, AMPH treatment decreased the total number of inflammatory cells, recovered in both BAL and peripheral blood and increased the total number of bone marrow cells. These effects, observed 1 day after OVA challenge, were abrogated by previous metyrapone treatment. Conclusion: AMPH treatment changed HPA-axis responsiveness to the stress condition imposed by the OVA challenge decreasing lung and blood leukocytes cellularity most probably via corticosterone actions on bone marrow activity.

Asthma is an inflammatory lung disease characterized by cell migration, bronchoconstriction and hyperresponsiveness, and can be induced, as an experimental model, by ovalbumin sensitization followed by a challenge. In addition to the well-known immunostimulatory effects of melatonin, research has identified some of its anti-inflammatory properties. In this study, we evaluated the influence of pinealectomy and melatonin administration on cell migration in an experimental model of allergic airway inflammation. We evaluated, in pinealectomized rats treated or not with melatonin, cell migration into the bronchoalveolar fluid, the number of cells and their proliferative activity in the bone marrow, and plasma corticosterone levels. Pinealectomy reduces, 24 hr after the challenge, the total cell number count in the lung and bone marrow cell proliferation, without changing the number of cells in the bone marrow or in the peripheral blood. This fact suggests that melatonin is important in the control of cell recruitment from the bone marrow and the migration of those cells to the lung. Melatonin administration to pinealectomized rats seems to restore the ability of cells to migrate from the bone marrow to the bronchoalveolar fluid. So, the development of specific inhibitors of melatonin would benefit patients with asthma.

Objective: Literature data suggest that rodent salivary glands can exert a neuroimmunomodulatory influence on distant inflammatory events. The release of regulatory factors by salivary glands appears to be influenced by time-dependent factors. In this paper we examined this possibility directly by studying the role of submandibular salivary glands in the temporal profile of lypopolysaccharide (LPS)-induced lung inflammation in rats. Methods: The submandibular glands were removed (SMGx) or not (sham) and, 4 days later, the animals received an intravenous LPS injection (Salmonella abortus equi, 1 mg/kg). Cells in peripheral blood and in bronchoalveolar and bone marrow lavages were quantified after 90 min, 1, 3 and 5 days. Tumor necrosis factor (TNF) activity and corticosterone concentrations in serum were also determined. Baseline values were determined in a group of naïve rats. Results: One day after the LPS injection, neutrophil counts in lungs and blood in both animal groups were elevated, but the SMGx rats presented a significantly lower response in comparison to the sham-operated controls. Five days after LPS treatment, however, SMGx rats had higher neutrophil counts in the lungs than did sham animals, but numbers of blood neutrophils were equal. Ninety minutes after LPS injection, a peak of serum TNF activity was detected in both groups compared with naïve levels. At this time point, TNF activity was about 135% higher in the serum of the SMGx group than in controls. Corticosterone levels of sham-operated controls rose only on the 5th day after LPS, whereas SMGx rats had significant peaks of corticosterone both on the 1st and the 5th day, but not on the 3rd day. Conclusion: Our data indicate that submandibular glands have a dual effect on inflammatory pulmonary response by differentially modulating the profile of lung neutrophil influx.