Channel blocker
Encyclopedia
A channel blocker or ion channel blocker (ICB) is a type of drug
which bind
s inside the pore of a specific type of ion channel
and blocks the flow of ions through it, resulting in an alteration of the electrochemical gradient
of the cell membrane
of neuron
s and therefore a change in neurotransmission
.
The following types which act on ligand-gated ion channel
s (LGICs) via binding to their pore also exist:
These types of receptor antagonist
s are referred to as noncompetitive or uncompetitive.
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...
which bind
Binding (molecular)
Molecular binding is an attractive interaction between two molecules which results in a stable association in which the molecules are in close proximity to each other...
s inside the pore of a specific type of ion channel
Ion channel
Ion channels are pore-forming proteins that help establish and control the small voltage gradient across the plasma membrane of cells by allowing the flow of ions down their electrochemical gradient. They are present in the membranes that surround all biological cells...
and blocks the flow of ions through it, resulting in an alteration of the electrochemical gradient
Electrochemical gradient
An electrochemical gradient is a spatial variation of both electrical potential and chemical concentration across a membrane; that is, a combination of the membrane potential and the pH gradient...
of the cell membrane
Cell membrane
The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It basically protects the cell...
of neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s and therefore a change in neurotransmission
Neurotransmission
Neurotransmission , also called synaptic transmission, is the process by which signaling molecules called neurotransmitters are released by a neuron , and bind to and activate the receptors of another neuron...
.
Types of Channel Blockers
There are several different major classes of channel blockers, including:- Calcium (Ca2+) channel blockerCalcium channel blockerA calcium channel blocker is a chemical that disrupts the movement of calcium through calcium channels.CCB drugs devised to target neurons are used as antiepileptics. However, the most widespread clinical usage of calcium channel blockers is to decrease blood pressure in patients with...
s - Chloride (Cl-) channel blockers
- Potassium (K+) channel blockerPotassium channel blockerPotassium channel blockers are agents which interfere with conduction through potassium channels.-Arrhythmia:Potassium channel blockers used in the treatment of cardiac arrhythmia are classified as class III antiarrhythmic agents.-Mechanism:...
s - Sodium (Na+) channel blockerSodium channel blockerSodium channel blockers are agents that impair conduction of sodium ions through sodium channels.-Extracellular:The following naturally produced substances block sodium channels by binding to and occluding the extracellular pore opening of the channel:...
s
The following types which act on ligand-gated ion channel
Ligand-gated ion channel
Ligand-gated ion channels are one type of ionotropic receptor or channel-linked receptor. They are a group of transmembrane ion channels that are opened or closed in response to the binding of a chemical messenger , such as a neurotransmitter.The binding site of endogenous ligands on LGICs...
s (LGICs) via binding to their pore also exist:
- 5-HT3 receptor antagonist5-HT3 antagonistThe 5-HT3 antagonists are a class of medications that act as receptor antagonists at the 5-HT3 receptor, a subtype of serotonin receptor found in terminals of the vagus nerve and in certain areas of the brain....
s - AMPA receptorAMPA receptorThe α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor is a non-NMDA-type ionotropic transmembrane receptor for glutamate that mediates fast synaptic transmission in the central nervous system . Its name is derived from its ability to be activated by the artificial glutamate analog AMPA...
antagonistReceptor antagonistA receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
s - GABAA receptor antagonistGABA antagonistGABA antagonists are drugs which inhibit the action of GABA. In general these drugs produce stimulant and convulsant effects, and are mainly used for counteracting overdose of sedative drugs....
s - Glycine receptorGlycine receptorThe glycine receptor, or GlyR, is the receptor for the amino acid neurotransmitter glycine. GlyR is an ionotropic receptor that produces its effects through chloride current...
antagonistReceptor antagonistA receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
s - Kainate receptorKainate receptorKainate receptors, or KARs, are non-NMDA ionotropic receptors which respond to the neurotransmitter glutamate. They were first identified as a distinct receptor type through their selective activation by the agonist kainate, a drug first isolated from red algae Digenea simplex. KARs are less well...
antagonistReceptor antagonistA receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
s - nACh receptor antagonistNicotinic antagonistA nicotinic antagonist is a type of anticholinergic that inhibits the action at nicotinic acetylcholine receptors. These compounds are mainly used for peripheral muscle paralysis in surgery, but some centrally acting compounds such as bupropion, mecamylamine, and 18-methoxycoronaridine block...
s - NMDA receptor antagonistNMDA receptor antagonistNMDA receptor antagonists are a class of anesthetics that work to antagonize, or inhibit the action of, the N-methyl d-aspartate receptor . They are used as anesthesia for animals and, less commonly, for humans; the state of anesthesia they induce is referred to as dissociative anesthesia...
s - P2X receptorP2X ReceptorP2X receptors are a family of cation-permeable ligand gated ion channels that open in response to the binding of extracellular adenosine 5'-triphosphate . They belong to a larger family of receptors known as the purinergic receptors...
antagonistReceptor antagonistA receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
s - Zinc (Zn2+)-activated channelZinc-activated ion channelZinc-activated ion channel , is a human protein encoded by the gene. ZAC forms a cation-permeable ligand-gated ion channel of the "Cys-loop" superfamily...
antagonistReceptor antagonistA receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
s
These types of receptor antagonist
Receptor antagonist
A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
s are referred to as noncompetitive or uncompetitive.