Potassium channels selectivity

Gao, Y. D., and Garcia, M. L. 2003. Interaction of agitoxin2, charybdotoxin, and iberiotoxin with potassium channels selectivity between voltage-gated and Maxi-K channels. Proteins 52 146-154. 

Opiates iateract with three principal classes of opioid GPCRs )J.-selective for the endorphiQS,5-selective for enkephalins, and K-selective for dynorphias (51). AU. three receptors have been cloned. Each inhibits adenylate cyclase, can activate potassium channels, and inhibit A/-type calcium channels. The classical opiates, morphine and its antagonists naloxone (144) and naltrexone (145), have moderate selectivity for the. -receptor. Pharmacological evidence suggests that there are two subtypes of the. -receptor and three subtypes each of the 5- and K-receptor. An s-opiate receptor may also exist. 

Doyle, D.A., et al. The structure of the potassium channel molecular basis of K+ conduction and selectivity. Science 280 69-77, 1998. 

Potassium channels are a diverse and ubiquitous family of membrane proteins present in both excitable and nonexcitable cells that selectively conduct K+ ions across the cell membrane along its electrochemical gradient at a rate of 106-108 ions/s. 

This peptide itself has no selectivity for the two CCK receptors, CCK-A and B, which have so far been established to stimulate IP3/DAG while, like substance P, can close potassium channels to increase neuronal activity. The CCK-B receptor is thought to predominate in the CNS but species differences may make this interpretation difficult. It has a wide distribution in the CNS but is also found in the gut whereas the CCK-A receptor is more restricted but is found in the hypothalamus, hippocampus and in the brainstem. There are high levels of the natural peptide, CCK-8 in cortex, hippocampus, hypothalamus, ventral tegmentum, substantia nigra, brainstem and spinal cord. CCK is one of the most abundant peptides in the brain and CCK co-exists with dopamine, substance P, 5-HT and vasopressin. Interestingly, in the dopamine areas, CCK co-exists in the mesolimbic pathways but in the nigrostriatal projections, the peptide and... 

Phencyclidine (PCP) Selectively Blocks Certain Presynaptic Potassium Channels... 

Noskov, S.Y. Berneche, S. Roux, B., Control of ion selectivity in potassium channels by electrostatic and dynamic properties of carbonyl ligands, Nature 2001,431, 830-834. 

Burykin, A. Kato, M. Warshel, A., Exploring the origin of the ion selectivity of the KcsA potassium channel, Proteins 2003, 52, 412-426. 

MacKinnon, R. (2004) Potassium channels and the atomic basis of selective ion conduction (Nobel Lecture). Angewandte Chemie-Intemational Edition, 43,... 

Figure 9.4 Structures of potassium channels in open and closed conformations. The selectivity filter is orange, and the conserved glycine residue is in red. (From Yu et al., 2005. Reproduced with permission of Blackwell Publishing Ltd.)...

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