Smooth-muscle constriction

Airway obstruction manifests itself as symptoms such as chest tightness, cough, and wheezing. Airway obstruction can be caused by multiple factors including airway smooth muscle constriction, airway edema, mucus hypersecretion, and airway remodeling. Airway smooth muscle tone is maintained by an interaction between sympathetic, parasympathetic, and non-adrenergic mechanisms. Acute bronchoconstriction usually... 

At the cellular level, eosinophils, mast cells, alveolar macrophages, lymphocytes and neutrophils recruited to the airways of asthmatics produce a variety of inflammatory mediators, such as histamine, kinins, neuropeptides, and leukotrienes, which lead to airway smooth muscle constriction and obstruction of airflow, and the perpetuation of airway inflammation [20, 21]. An understanding of the inflammatory processes and the molecular pathways of these mediators has led to the development and widespread use of several pharmacologic agents that mitigate airway inflammation and bronchoconstriction. 

Mast cell degranulation in response to allergens results in release of mediators such as histamine eosinophil, and neutrophil chemotactic factors leukotrienes C4, D4, and E4 prostaglandins and platelet-activating factor (PAF). Histamine is capable of inducing smooth muscle constriction and bronchospasm and may play a role in mucosal edema and mucus secretion. 

Muscular tissue Smooth muscle Constricts tubular walls... 

May have agonist/antagonist actions with alpha adrenergic, serotonergic, dopaminergic receptors. Directly stimulates vascular smooth muscle, constricting arteries and veins. May inhibit reuptake of norepinephrine. 

Asthma is characterized by either the intermittent or persis- tent presence of highly variable degrees of airway obstruction from airway wall inflammation and bronchial smooth muscle constriction. 

Bronchial smooth muscle constriction is prevented or treated most effectively with inhaled /32-adrenergic receptor agonists. 

The prostaglandins are a new family of acidic lipids which are present in many, if not all, mammalian tissues and which have a wide variety of striking pharmacological properties both in vivo and in vitro. Individual prostaglandins in exceedingly small doses may stimulate or relax the uterus and Fallopian tubes, stimulate intestinal smooth muscle, constrict the pupil, dilate peripheral and coronary arteries, constrict veins, constrict nasal and placental blood-vessels, excite or... 

A reduced FEV,/FVC ratio is the most common lung function abnormahty. The usual causes are asthma, vdiere the obstruction is due to inflammation and smooth muscle constriction in the large and small airways, to emphysema, where the problem is collapse of the airways that lack support in expiration, and obstructive bronchitis, where the main problem is small airway fibrosis and inflammation. COPD is an umbrella term to encompass emphysema and obstructive bronchitis, which usually coexist. Other less common causes include bronchiectasis, obstruction by extrinsic compression, tumour or foreign body. In clinical practice, the most difficult distinction is between asthma and COPD. By definition, asthma... 

Large exposures to nerve agent vapours can result in severe bronchiolar smooth muscle constriction (bronchospasm), wheezing, copious secretions from bronchial cells (bronchorrhea) and ventilatory failure. At this level, rhinorrhoea becomes a marked sign and the secretions become a major factor in airway blockage. 

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