neuron. The opioid receptors have the following channel types: Mu, K+ channel; l Delta, K+ channel; Kappa, Ca2+ channel. Hyperpolarization can lead to post-synaptic neural inhibition and presynaptic inhibition of neurotransmitter release. Post-synaptic neural inhibition can reduce analgesia and central hyperactivity may reduce its efficacy. The mechanism of Kappa receptors is slightly different than Mu and Delta, in that Ca2+ channels close instead of K+ channels, and K+ channels open in mu and delta. See also Commission on Narcotic Drugs East African drug trade Equianalgesic Narcoterrorism Narcotics Anonymous Opioid Prohibition of drugs War on drugs References External links Pharmer.org—A non-profit site providing detailed descriptions of most narcotic analgesics List of controlled substances, some of which are classified as "narcotics", in the U.S. Controlled Substances Act (CSA). Not all of the classified ones are chemically narcotic, as described at the top of this page. Opioids