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 alpha(1A) and alpha(1B)- adrenergic receptor and effect of Salbutamol as agonist of beta(2)- 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 alpha(1A) and alpha(1B)- 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 beta(2)- 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 alpha(1A) and alpha(1B)- 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 beta(2) – adrenergic receptor which emphasizes their significant action in the reduction of specific resistance of airways.