Related Experiment Video
Updated: May 12, 2026
10:20
In vitro Measurements of Tracheal Constriction Using Mice
Published on: June 25, 2012
Normal alpha 2-adrenergic responses in platelets from patients with asthma
The Journal of Allergy and Clinical Immunology
|January 1, 1982
Summary
Platelet alpha 2-adrenergic responses, which regulate cyclic adenosine monophosphate (cAMP) accumulation, were found to be normal in asthma patients. This suggests that exaggerated alpha-adrenergic responses in asthma may not involve platelet alpha 2-adrenergic pathways.
Area of Science:
- Pharmacology
- Respiratory Medicine
- Cellular Biology
Background:
- Recent in vivo studies indicate heightened alpha-adrenergic responses in individuals with asthma.
- Platelets are utilized as a model to investigate systemic alpha-adrenergic function.
Purpose of the Study:
- To investigate alpha 2-adrenergic responses in platelets of healthy subjects and patients with asthma.
- To determine if alpha 2-adrenergic inhibition of cyclic adenosine monophosphate (cAMP) accumulation differs between asthmatic and healthy individuals.
Main Methods:
- Studied alpha 2-adrenergic responses in platelets from 12 healthy subjects and 10 asthma patients.
- Assessed alpha 2-adrenergic inhibition of prostaglandin E1-stimulated cAMP accumulation.
- Compared time course, extent, and dose-response relationships of cAMP inhibition.
Main Results:
- Alpha 2-adrenergic inhibition of cAMP accumulation was normal in platelets from asthma patients.
- No significant differences were observed in the time course, extent, or dose-response of inhibition between groups.
- Results were consistent across allergic and non-allergic patients and showed no correlation with clinical parameters.
Conclusions:
- Platelet alpha 2-adrenergic cAMP responses are normal in subjects with asthma.
- Exaggerated alpha-adrenergic responses in asthma may not be mediated by platelet alpha 2-adrenergic pathways.
Related Concept Videos
01:27Adrenergic Receptors (Adrenoceptors): Classification
Adrenergic receptors, or adrenoceptors, respond to the autonomic neurotransmitter noradrenaline and other endogenous catecholamine agonists. They are classified into two main families, α and β, based on their pharmacological response and are further subdivided depending on their location, elicited response, and affinity to specific agonists or antagonists.
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
01:31Adrenergic Receptors: ɑ Subtype
Adrenoceptors are classified into α and ꞵ classes based on their potencies to catecholamine agonists. α-adrenoceptors show the following order of catecholamine potency:
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
01:26Adrenergic Receptors: β Subtype
β-adrenoceptors have varied sensitivities towards adrenaline, noradrenaline, and isoprenaline. The order of agonist potency is as follows:
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
01:30Adrenergic Agonists: Therapeutic Uses
Adrenergic agonists have diverse therapeutic uses across various medical conditions and emergencies.
Emergency and Intensive Care Unit (ICU) applications: Pressor agents increase blood pressure, heart rate, and contractility in shock and organ failure situations. Dopamine can induce vasodilation and stimulate adrenoceptors. Endogenous catecholamines are effective in treating cardiogenic shock. α2-agonists like clonidine can reverse anesthesia-induced hypertension.
Allergies and anaphylaxis:...
Emergency and Intensive Care Unit (ICU) applications: Pressor agents increase blood pressure, heart rate, and contractility in shock and organ failure situations. Dopamine can induce vasodilation and stimulate adrenoceptors. Endogenous catecholamines are effective in treating cardiogenic shock. α2-agonists like clonidine can reverse anesthesia-induced hypertension.
Allergies and anaphylaxis:...
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...
01:26Asthma-II: Pathophysiology and Classification
Asthma is a prevalent chronic respiratory condition marked by inflammation and hyperresponsiveness of the airways. Its pathophysiology involves complex interactions among inflammatory pathways, immune responses, and neural mechanisms.
Additionally, environmental and genetic factors play crucial roles in determining an individual's susceptibility to asthma and the severity of their condition.
Critical processes in asthma pathophysiology include:
Additionally, environmental and genetic factors play crucial roles in determining an individual's susceptibility to asthma and the severity of their condition.
Critical processes in asthma pathophysiology include: