Mechanism of Action
See also: Adrenergic receptor| Organ | Effects |
|---|---|
| Heart | Increases heart rate |
| Lungs | Increases respiratory rate |
| Systemic | Vasoconstriction or vasodilation |
| Liver | Stimulates glycogenolysis |
| Systemic | Triggers lipolysis |
| Systemic | Muscle contraction |
As a hormone and neurotransmitter, adrenaline acts on nearly all body tissues. Its actions vary by tissue type and tissue expression of adrenergic receptors. For example, high levels of adrenaline causes smooth muscle relaxation in the airways but causes contraction of the smooth muscle that lines most arterioles.
Adrenaline acts by binding to a variety of adrenergic receptors. Adrenaline is a nonselective agonist of all adrenergic receptors, including the major subtypes α1, α2, β1, β2, and β3. Epinephrine's binding to these receptors triggers a number of metabolic changes. Binding to α-adrenergic receptors inhibits insulin secretion by the pancreas, stimulates glycogenolysis in the liver and muscle, and stimulates glycolysis in muscle. β-Adrenergic receptor binding triggers glucagon secretion in the pancreas, increased adrenocorticotropic hormone (ACTH) secretion by the pituitary gland, and increased lipolysis by adipose tissue. Together, these effects lead to increased blood glucose and fatty acids, providing substrates for energy production within cells throughout the body.
Read more about this topic: Epinephrine
Famous quotes containing the words mechanism of, mechanism and/or action:
“The two elements the traveler first captures in the big city are extrahuman architecture and furious rhythm. Geometry and anguish. At first glance, the rhythm may be confused with gaiety, but when you look more closely at the mechanism of social life and the painful slavery of both men and machines, you see that it is nothing but a kind of typical, empty anguish that makes even crime and gangs forgivable means of escape.”
—Federico García Lorca (1898–1936)
“The two elements the traveler first captures in the big city are extrahuman architecture and furious rhythm. Geometry and anguish. At first glance, the rhythm may be confused with gaiety, but when you look more closely at the mechanism of social life and the painful slavery of both men and machines, you see that it is nothing but a kind of typical, empty anguish that makes even crime and gangs forgivable means of escape.”
—Federico García Lorca (1898–1936)
“Do you suppose that sacrifice is the hallmark of moral action?—Just stop to consider whether sacrifice is not involved in every action that is done with deliberation, the worst as well as the best.”
—Friedrich Nietzsche (1844–1900)