1. Ion Channels

2. Cell membrane

3. Voltage-gated Ion Channels voltage-gated because they open and close depending on the electrical potential across the membrane.

4. Chemically-gated Ion Channels Ligand-gated ion channels G-protein coupled receptors

5. Membrane potential

6. Subunit structure of the voltage-gated sodium channels

7. Amino acid sequence similarity and phylogenetic relationships of voltage-gated sodium channel  subunits The nine sodium channel isoforms may be considered members of one protein family.

8. RECEPTOR DATABASE http://www.iuphar-db.org/GPCR/index.html