Response of smooth bronchial musculature in bronchoconstrictor substances in newborn with lung atelectasis at the respiratory distress syndrome (RDS).

OBJECTIVE: Role of the atelectasis (hypoxia) in the respiratory system of the live and exited newborn (250 up to 3000 g. of body weight), which has died due to different causes was studied in this work. METHODS: Response of tracheal rings to dopamine, serotonine and ethanol in the different molar concentrations (dopamine: 0.05 mg/ml, 0.5 mg/ml, 5 mg/ml; serotonine (5-HT): 10(-4), 10(-3), 10(-2), 10(-1) mol/dm3; ethanol: 0.2 ml, 0.5 ml, 1.0 ml; 96%) was followed up. Study of the smooth tracheal musculature tone (STM) was elaborated in 16 tracheal preparations taken following the newborn death due to different causes. RESULTS: Based on functional researches of tracheal isolated preparations, it was ascertained as follows: atelectasis (cases born with lung hypoxia) has changed the response of STM to dopamine, serotonine and ethanol in a significant manner (p < 0.01) in comparison to cases of controlling group, which has died due to lung inflammatory processes (e.g. pneumonia, bronchopneumonia, cerebral hemorrhage), which have also caused significant response (p < 0.05). CONCLUSION: Results suggest that exited cases from lung atelectasis and cases of controlling group reacts to above mentioned substances by causing significant constrictor action of tracheobronchial system.

Response of the adrenergic system after provoked bronchoconstriction in patients with bronchial asthma.

OBJECTIVE: In this paper, effect of the Tolazoline as antagonist of the alpha-2 adrenergic receptors in patients with bronchial asthma and chronic obstructive bronchitis was studied, and also the effect of stimulation with Hexoprenaline of beta-2 adrenergic receptor after bronchi-constriction caused with Propranolol, and Acetylcholine. METHODS: Lung function parameters are determined with Body plethysmography. In patients with bronchial asthma and chronic obstructive bronchitis was registered resistance (Raw), was determined the amount of intrathoracic gas volume (ITGV), and specific resistance was calculated as well (SRaw). Aerosolization was done with standard aerosolizing machine-Asema. RESULTS: The study included a total of 21 patients. Two hours after the inhalation of Propranolol, in experimental group, it was applied the blocker of alpha-2 adrenergic receptors (Tolazoline 20 mg / ml with inhalator ways), which did not cause changes in bronchomotor tonus of tracheobronchial system (p > 1.0). Meanwhile, at the same patient, stimulation of beta-2 adrenergic receptor with Hexoprenaline (2 inh x 0.2 mg) is associated with a significant decrease of the specific resistance of airways (SRaw, p < 0.01). Control group results show that after bronchi-constriction caused by Propranolol-aerosol (20 mg / ml) in patients with bronchial asthma and chronic obstructive bronchitis, an increase of specific resistance in airways was caused (SRaw, p < 0.01), which confirms the presence of hyper-reactive bronco-constrictor effects intermediated by vagal ways. Two hours after Propranolol, inhaled Hexorenaline has blocked the action of Propranolol, but not entirely. Furthermore, two hours after acetylcholine-aerosol (1 mg /ml) was applied, inhaled Ipratropium (2 inh x 1 mg) has fully blocked the action of chemical bronchoconstrictor mediators, causing a decline of specific resistance in the airways (SRaw; p < 0.01). CONCLUSION: This suggests that primary mechanism, which would cause reaction in patients with increased bronchial reactibility, is prevalence of the cholinergic system over adrenergic one, and not the relationship in between alpha-2 and beta-2 adrenergic receptors.