Related Concept Videos

Antidotes01:17

Antidotes

Antidotes are medicinal substances used to counteract the harmful effects of toxins or drugs in the body. They function in various ways, each uniquely designed to combat specific toxic compounds.
Specific antidotes operate by inhibiting the enzymes that control biochemical pathways, reducing the production of harmful metabolites.
An example of an antidote is atropine, which counteracts the detrimental effects of cholinesterase inhibitors. It achieves this by deactivating muscarinic receptors,...
Principles of Drug Action01:24

Principles of Drug Action

Drugs are chemical substances that modify biological responses by interacting with macromolecular targets such as receptors, ion channels, transporters, and enzymes. Pharmacodynamics describes the course of action of drugs leading to the physiological effect at a specific site in the body.
Drugs can be agonists or antagonists. Like the endogenous ligands, agonists always bind and activate the target to produce a cellular response. Agonist binding induces a conformational change which in turn...
Indirect-Acting Cholinergic Agonists: Mechanism of Action01:18

Indirect-Acting Cholinergic Agonists: Mechanism of Action

Indirect-acting cholinergic agonists work by interacting with an enzyme called acetylcholinesterase (AChE) in the synaptic cleft. They can be reversible or irreversible inhibitors and have different effects on the enzyme.
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
Indirect-Acting Cholinergic Agonists: Pharmacokinetics01:22

Indirect-Acting Cholinergic Agonists: Pharmacokinetics

Indirect-acting cholinergic agonists, or anticholinesterases, enhance the body's cholinergic activity by inhibiting acetylcholine's breakdown. They are categorized as reversible or irreversible agents based on their mechanism of action. They are further classified into short-acting, intermediate-acting, and long-acting agents based on their duration of action.
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they are...
Indirect-Acting Cholinergic Agonists: Pharmacological Actions01:30

Indirect-Acting Cholinergic Agonists: Pharmacological Actions

Indirect-acting cholinergic agonists, also known as anticholinesterases, exert their pharmacological effects by enhancing cholinergic transmission in various body parts, including the neuromuscular junction, autonomic cholinergic synapses, and the brain.
At the neuromuscular junction, these agents work by inhibiting the breakdown of acetylcholine, allowing it to remain bound to the receptor and bind to nearby receptors. This process leads to repetitive firing of the endplate, causing muscle...
Anticholinesterase Agents: Poisoning and Treatment01:26

Anticholinesterase Agents: Poisoning and Treatment

Anticholinesterases, also known as cholinesterase inhibitors, work by blocking the breakdown of acetylcholine, leading to its accumulation in the synaptic cleft. This accumulation indirectly enhances both muscarinic and nicotinic actions. These agents are classified as reversible or irreversible based on their mechanism of action.     
Irreversible agents form a strong bond with the cholinesterase enzyme, making it inactive. The breakdown of the phosphorylated enzyme is slower than the...