Pharmacologic Antagonists
Pharmacologic Antagonists - Related Videos
01:28
Cholinergic Antagonists: Pharmacological Actions
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2023
Antimuscarinic drugs block muscarinic receptors in multiple systems, including the gut, eye, smooth muscles, respiratory tract, cardiovascular, and central nervous systems. They produce similar effects with varying selectivity depending on the specific agent and tissue. Here are the key pharmacological actions of antimuscarinics: Gastrointestinal Effects: Antimuscarinics reduce gut contractions, increase gastric emptying, and slow intestinal transit. They partly inhibit gastric acid secretion...
01:22
Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers
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2023
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...
01:27
Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers
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2023
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...
06:52
Manufacturing and Using Piggy-back Multibarrel Electrodes for In vivo Pharmacological Manipulations of Neural Responses
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Cited by 8 •
2013
Iontophoresis of neural agonists and antagonists during extracellular in vivo recordings is a powerful way to manipulate a neuron’s microenvironment. These manipulations can most easily be done via piggy-back multibarrel electrodes. Here we describe how to manufacture them and use them during auditory recordings.
11:32
Real-Time, High-Throughput Microscopic Quantification of Human Neutrophil Extracellular Trap Release and Assessing the Pharmacology of Antagonists
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Cited by 3 •
2024
This defined protocol describes a real-time high-throughput microscopy approach to visualize and quantify human neutrophil extracellular trap (NET) release in vitro. The reproducible method allows investigation of the characteristics and kinetics of NET release upon stimulation with distinct NETosis inducers and enables assessment of the pharmacology of NETosis antagonists.
FAQs
Competitive antagonists reversibly occupy the same receptor binding site used by an agonist. Because this interaction is reversible, the antagonist and agonist compete for access to that site, changing whether receptor activation can occur. This mechanism provides a way to reduce agonist effects while preserving the distinction between temporary site occupancy and more persistent forms of blockade.
Noncompetitive antagonists reduce signaling through either irreversible receptor binding or interaction with a different receptor site. Their effect therefore does not depend solely on competing with an agonist for the same reversible binding location. This distinction matters when researchers need to examine reduced receptor signaling that arises from more persistent binding or from altered receptor-site interactions.
Receptor activation initiates the signaling responses through which agonists produce physiological effects. By preventing that activation or reducing the resulting signaling, antagonists can counter excessive responses and limit the consequences of an agonist. This receptor-level control makes them useful for connecting drug binding with pathway activity and for managing the intensity of pharmacological effects.
Opioid antagonists are used to reverse opioid effects by preventing opioid-associated receptor activation. Their application illustrates how receptor blockade can counter an excessive physiological response rather than produce the agonist response itself. In pharmacology, this example demonstrates the therapeutic value of interrupting receptor-mediated pathways when the effects of another drug need to be reduced.
Beta-adrenergic antagonists provide a cardiovascular application of receptor-mediated control. By blocking beta-adrenergic receptor effects, they can help manage cardiovascular conditions, as noted in the source material. Their importance lies in limiting signaling from an agonist pathway, showing how antagonism can be applied therapeutically beyond reversal of acute drug effects.
Researchers can use antagonists to interrupt specific receptor-mediated pathways and observe the resulting change in signaling or physiological response. Comparing outcomes with and without receptor blockade helps identify the contribution of that receptor to an agonist effect. This experimental use extends antagonists beyond treatment, making them tools for analyzing receptor function in pharmacological research.
Antagonists are especially valuable when a physiological response becomes excessive or when the effects of another drug must be limited. Their ability to block receptor activation or reduce downstream signaling provides a mechanism for controlling the magnitude of an agonist response. Opioid-effect reversal and cardiovascular management illustrate two different therapeutic contexts for this principle.