Importance of Alpha-adrenergic Receptor Subtypes in Regulating of Airways Tonus at Patients with Bronchial Asthma

BACKGROUND In this work, effect of Tamsulosin hydrochloride as antagonist of alpha1A and alpha1B- adrenergic receptor and effect of Salbutamol as agonist of beta2- adrenergic receptor in patients with bronchial asthma and increased bronchial reactibility was studied. METHODS Parameters of the lung function are determined by Body plethysmography. Raw and ITGV were registered and specific resistance (SRaw) was also calculated. Tamsulosin was administered in per os way as a preparation in the form of the capsules with a brand name of "Prolosin", producer: Niche Generics Limited, Hitchin, Herts. RESULTS Results gained from this research show that blockage of alpha1A and alpha1B- adrenergic receptor with Tamsulosin hydrochloride (0.4 mg and 0.8 mg in per os way) has not changed significantly (p > 0.1) the bronchomotor tonus of tracheobronchial tree in comparison to the inhalation of Salbutamol as agonist of beta2- adrenergic receptor (2 inh. x 0.2 mg), (p < 0.05). Arterial blood pressure showed no significant decrease following the administration of the dose of 0.8 mg Tamsulosin. CONCLUSION This suggests that the activity of alpha1A and alpha1B- adrenergic receptor in the smooth musculature is not a primary mechanism which causes reaction in patients with increased bronchial reactibility, in comparison to agonists of beta2 - adrenergic receptor which emphasizes their significant action in the reduction of specific resistance of airways.