Write a note on ligand gated channels.
Answers
Ligand-gated ion channels (LICs, LGIC), also commonly referred to as ionotropic receptors, are a group of transmembrane ion-channel proteins which open to allow ions such as Na+, K+, Ca2+, and/or Cl− to pass through the membrane in response to the binding of a chemical messenger (i.e. a ligand), such as a neurotransmitter.
Resting membrane potential: The electrical potential across the plasma membrane of a neuron in the absence of a stimulus. Value ranges from -40 to -90mV.
Action potential: A series of sudden changes in the electrical potential across the plasma membrane of the neuron, produced in response to a stimulus. Peak value can be as high as +50mV.
Depolarization: The process by which the membrane potential across the neuronal plasma membrane becomes more positive than the resting potential.
Repolarization: The process by which the membrane potential across the neuronal membrane is restored to the original resting membrane potential.
Threshold potential: The level of the membrane potential at which an action potential occurs.
Refractory period: The interval during which a Na+ channel (which opened in response to an action potential) is inactivated and unresponsive to subsequent action potentials.