Adenosine-triphosphate -sensitive channels

Aguilar-Bryan L, Bryan J (1999) Molecular biology of adenosine triphosphate-sensitive potassium channels. Endocr Rev 20 101-135... 

Tricarico D, Servidei S, Tonali P, Jurkat-Rott K, Camerino DC (1999) Impairment of skeletal muscle adenosine triphosphate-sensitive K+ channels in patients with hypokalemic periodic paralysis. J Clin Invest 103 675-682. 

Jeppesen PB, Gregersen S, Poulsen CR, Hermansen K (2000) Stevioside acts directly on pancreatic (3 cells to secrete insulin actions independent of cyclic adenosine monophosphate and adenosine triphosphate-sensitive K-l—channel activity. Metabolism 49 208-214 Abudula R, Jeppesen PB, Rolfsen SED, Xiao J, Hermansen K (2004) Rebaudioside A potentially stimulates insulin secretion from isolated mouse islets studies on the dose-, glucose-, and calcium-dependency. Metabolism 53 1378-1381... 

The sulfonylurea receptor was identified as an adenosine triphosphate (ATP) sensitive potassium (Katp) channel that is present on the (3-cell membrane surface. Closure of these K tp channels causes (3-cell membrane... 

Schematic illustration of a generalized cholinergic junction (not to scale). Choline is transported into the presynaptic nerve terminal by a sodium-dependent choline transporter (CHT). This transporter can be inhibited by hemicholinium drugs. In the cytoplasm, acetylcholine is synthesized from choline and acetyl -A (AcCoA) by the enzyme choline acetyltransferase (ChAT). Acetylcholine is then transported into the storage vesicle by a second carrier, the vesicle-associated transporter (VAT), which can be inhibited by vesamicol. Peptides (P), adenosine triphosphate (ATP), and proteoglycan are also stored in the vesicle. Release of transmitter occurs when voltage-sensitive calcium channels in the terminal membrane are opened, allowing an influx of calcium. The resulting increase in intracellular calcium causes fusion of vesicles with the surface membrane and exocytotic expulsion of acetylcholine and cotransmitters into the junctional cleft (see text). This step can he blocked by botulinum toxin. Acetylcholine s action is terminated by metabolism by the enzyme acetylcholinesterase. Receptors on the presynaptic nerve ending modulate transmitter release. SNAPs, synaptosome-associated proteins VAMPs, vesicle-associated membrane proteins.

Other drugs affect intracellular calcium channels of the endoplasmic or sarcoplasmic reticulum, e.g. inositol triphosphate receptor channels open in response to InsPs itself and certain other inositol phosphates, are sensitized by thiomersal (which increases the sensitivity of the receptor to InsPs by acting as a sulphydryl reagent) and antagonized by heparin. The various ryanodine receptor channels, at which a putative natural agonist is cyclic adenosine diphosphate ribose (cADP-R), are activated by caffeine and low concentrations of ryanodine (but antagonized by high concentrations of ryanodine and ruthenium red). 

Adenosine-5 -triphosphate-sensitive ion channels in neonatal rat cultured central neurons. Pfugers Arch Eur J Physiol 412 297-304. 

And what happens with diabetes mellitus In 525 Caucasian type 2 diabetic patients, the common E23K variant of KCNJll encoding the pancreatic P-cell adenosine 5 -triphosphate-sensitive potassium channel subunit Kir6.2 was associated with increased risk for secondary failure to treatment with sulfonylurea-like glibenclamide [106]. 

Potassium ion channels are a veiy diverse family of membrane proteins, with numerous sub-types both in the CNS and peripheral tissues, in particular in the heart. On the basis of the amino acid sequence of the pore-forming a sub-unit, they are classified into two main super-families, the inward rectifier superfamily (which includes receptor-coupled, adenosine 5 -triphosphate (ATP)-sensitive and voltage-dependent channels) and the Sha/cer-related superfamily (which includes Ca2-H-dependent channels). 

ASPPR, aspartate protease ATP, adenosine 5 -triphosphate 5 -ATP, adenosine 5 -triphosphate ATP-K+ CH, ATP-sensitive K+ channel ATP-R, ATP receptor autophos n, autophosphorylation... 

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