Conotoxins have become a very important source for the development of marine peptide drugs, which target various receptors, ion channels, etc., with high selectivity, such as nicotinic acetylcholine receptors, sodium channels, potassium channel, calcium channel, and other relevant receptors, transporters, etc. The targets of conotoxins are involved in many human diseases, including pain, addiction, depression, autoimmune disease, cancers, etc. [8,36,37,38,39]. The gene discussed is KCNA3; the disease is major depressive disorder.