Ion channels and neurotransmitter receptors in the central nervous system include voltage-gated calcium and potassium channels that respond to changes in membrane potential, and ligand-gated channels that open when neurotransmitters bind to receptor subunits forming an integral channel complex. Communication between neurons occurs through chemical synapses. Drugs can act at various sites including transmitter synthesis, storage, release, reuptake, degradation, and receptors to increase or decrease ion conductance. The brain is organized into hierarchical and diffuse neuronal systems.

1. Intro to Pharmacology of CNS
Drugs
Dr Sumera Feroze

2. Ion Channels & Neurotransmitter
Receptors
• Voltage-gated channels
.Respond to changes in the membrane
potential of the cell
.voltage-sensitive calcium and potassium
channels on the cell body, dendrites, and
initial segment

3. • Ligand-gated channels or ionotropic receptors
• open by the binding of neurotransmitters to
the channel.
• The receptor is formed of subunits, and the
channel is an integral part of the receptor
complex

5. The Synapse & Synaptic Potentials
• The communication between neurons in the
CNS occurs through chemical synapses

7. Sites of drug action.
(1) Action potential in presynaptic fiber
(2) synthesis of transmitter
(3) storage
(4) metabolism
(5) release
(6) reuptake
(7) degradation
(8) receptor for the transmitter;
(9) receptor-induced increase or decrease in ionic
conductance.

8. Cellular Organization of the Brain
• Hierarchical systems
• nonspecific or diffuse neuronal systems.