From Acupuncture to Interaction between -Opioid Receptors and Na+ Channels: A Potential Pathway to Inhibit Epileptic Hyperexcitability
Table 2
Voltage-gated sodium channels.
Subunit
Subtypes
Nav1.1–Nav1.9
1–4
Location
Prevalent in the CNS:
Two subunits associated with an α subunit
Nav1.1, Nav1.2, Nav1.3, and Nav1.6
Abundant in muscle:
Nav1.4, Nav1.5
Primarily in peripheral nervous system:
Nav1.7, Nav1.8, and Nav1.9
Cellular distribution
Primary localized in cell body:
Expressed in a complementary fashion (either 1 or 3, and 2 or 4) with subunit
Nav1.1 and Nav1.3
High expression in unmyelinated or pre myelinated axons and dendrites:
Nav1.2
Nodes of Ranvier and axon initial segments as well as in the somata and dendrites of many projection neurons:
Nav1.6
Function
Forms the ion-conducting pore and activation and inactivation gates
Modify the kinetics and voltage dependence of gating Serve as cell adhesion molecules for integrating the channels into the appropriate subcellular domains