Related Experiment Video
Updated: May 26, 2026
14:39
Bronchial Thermoplasty: A Novel Therapeutic Approach to Severe Asthma
Published on: November 4, 2010
Alpha-adrenoceptor blocking drugs in asthma.
1Department of Respiratory Medicine, Western Infirmary, Glasgow.
British Journal of Clinical Pharmacology
|January 6, 2012
Summary
Thymoxamine enhances isoprenaline
Area of Science:
- Pharmacology
- Respiratory Medicine
- Asthma Research
Background:
- Extrinsic asthma involves airway hyperresponsiveness.
- Alpha-adrenoceptors play a role in airway smooth muscle tone.
- Isoprenaline is a bronchodilator used in asthma treatment.
Purpose of the Study:
- To investigate the effect of thymoxamine, an alpha-adrenoceptor blocker, on specific airways conductance (SGaw) in extrinsic asthma patients.
- To determine if thymoxamine potentiates the bronchodilating effects of isoprenaline.
Main Methods:
- Ten patients with extrinsic asthma were recruited.
- Specific airways conductance (SGaw) was measured.
- The effects of thymoxamine alone and in combination with isoprenaline were assessed.
Main Results:
- Thymoxamine combined with isoprenaline resulted in a significantly greater increase in SGaw compared to isoprenaline alone.
- This suggests a synergistic effect between thymoxamine and isoprenaline on bronchodilation.
Conclusions:
- Thymoxamine potentiates isoprenaline-induced bronchodilation in extrinsic asthma.
- This potentiation may be mediated by increased cyclic AMP formation in bronchial smooth muscle.
- Alpha-adrenoceptor blockade could be a therapeutic strategy to enhance bronchodilator efficacy.
Related Concept Videos
01:25Antiasthma Drugs: β2-Adrenoceptor Agonists
Bronchodilators are critical in managing asthma, a chronic respiratory condition characterized by airway constriction due to inflammation and hyper-reactivity. Specifically, bronchodilators ease this constriction by relaxing the bronchial muscles, facilitating easier breathing.
One class of bronchodilators includes β2-adrenoceptor agonists. These agents target the β2-adrenoceptors located on bronchial smooth muscle cells. By stimulating these receptors, β2-agonists induce relaxation in these...
One class of bronchodilators includes β2-adrenoceptor agonists. These agents target the β2-adrenoceptors located on bronchial smooth muscle cells. By stimulating these receptors, β2-agonists induce relaxation in these...
01:22Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers
α-Adrenergic antagonists, known as α-blockers, exert their effects by inhibiting α-adrenoceptors, leading to specific physiological actions. α1-blockers and α2-blockers have distinct pharmacological actions and therapeutic applications.
α1-blockers: These drugs inhibit α1-adrenoceptors on smooth muscle cells, resulting in vasodilation. This vasodilation lowers blood pressure, making α1-blockers valuable in treating hypertension. Additionally, α1-blockers effectively address urinary obstruction...
α1-blockers: These drugs inhibit α1-adrenoceptors on smooth muscle cells, resulting in vasodilation. This vasodilation lowers blood pressure, making α1-blockers valuable in treating hypertension. Additionally, α1-blockers effectively address urinary obstruction...
01:17Adrenergic Antagonists: Chemistry and Classification of ɑ-Receptor Blockers
Adrenergic antagonists, or sympatholytics, inhibit adrenoceptor activation driven by catecholamines or agonists. Based on their adrenoceptor specificity, adrenergic blockers can be categorized into two primary groups: α-adrenergic blockers (α-blockers) and β-adrenergic blockers (β-blockers). α-blockers interact with α1 and α2 subtypes of α-adrenoceptors.
Nonselective α-blockers: Nonselective α-blockers contain haloalkylamine or imidazoline moieties. Phenoxybenzamine, with a haloalkylamine...
Nonselective α-blockers: Nonselective α-blockers contain haloalkylamine or imidazoline moieties. Phenoxybenzamine, with a haloalkylamine...
01:19Antiasthma Drugs: Leukotriene Modifiers
Leukotriene modifiers, or cysteinyl leukotriene receptor antagonists, are medications used to manage chronic asthma. These agents target specific inflammatory mediators produced during arachidonic acid metabolism, an essential process in generating inflammation in the body.
Leukotriene modifiers work through two distinct mechanisms:
Leukotriene modifiers work through two distinct mechanisms:
01:27Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers
β-receptor blockers significantly impact the cardiovascular system by counteracting catecholamine-induced sympathetic responses. These medications decrease heart rate, contractility, and cardiac output, potentially leading to cardiac depression, life-threatening bradycardia, and death. Therapeutically, β-blockers function as mild antihypertensives and are utilized in treating angina pectoris and cardiac arrhythmias. However, nonselective β-blockers inhibit β2-receptors in bronchial smooth...
01:20Antiasthma Drugs: Muscarinic Receptor Antagonists
Muscarinic receptor antagonists, also known as antimuscarinic agents, are a class of bronchodilators used to treat asthma, although they are more commonly used to treat COPD. They work by inhibiting the action of acetylcholine (ACh), a neurotransmitter, on muscarinic receptors found in the airways.
Antimuscarinic agents compete with ACh for the same binding site on the muscarinic receptors. By binding to these receptors, they inhibit the downstream effects of ACh and block the parasympathetic...
Antimuscarinic agents compete with ACh for the same binding site on the muscarinic receptors. By binding to these receptors, they inhibit the downstream effects of ACh and block the parasympathetic...