Cell Signaling Flashcards
Paracrine Signaling
a form of signaling where a cell produces a signal to induce changes in nearby cells
properties of Paracrine agents
rapidly degraded, only effects local tissue, does not enter the blood stream
Autocrine signaling
a form of signaling where a cell secretes a hormone or chemical messenger that binds to the same cell to induce changes in the same cell
properties of Autocrine agents
action on the same cell that secreted them
responses of Autocrine agents are mediated by receptors in the
membrane, cytoplasm, and nucleus
Eicosanoids
locally acting fatty acid hormones, made from arachidonic acid, located in the plasma membrane
Eicosanoids examples
Prostaglandin
Thromboxane
Leukotrienes
Phospholipase A2
converts phospholipid to Arachidonic acid
inhibited by Glucocorticoids
Cyclooxygenase
converts arachidonic acid to Endoperoxides
inhibited by Aspirin and NSAIDs
Subtypes of Cyclooxygenase
COX 1 - platelet aggregation pathway, protects stomach
COX 2 - pain and inflammation pathway
COX 3 - fever link? (recently discovered)
Prostacyclin Synthase (PGI2, prostaglandin I2)
vasodilator, bronchodilator, decreased platelet aggregation
Thromboxane Synthetase (TxA2)
vasoconstrictor, bronchoconstrictor, increased platelet aggregation
Leukotrienes
involved in asthmatic and allergic reactions, stimulated T cells, interleukin, interferon production, bronchoconstriction, increased vascular permeability
Action of NSAIDs and Aspirin
inhibits Cyclooxygenase
Aspirins
anticlotting pathways, can lead to ulcers
Ibuprofens
inhibit inflammatory reaction in pathway (PGI2) inhibits COX 1 & 2