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A-type potassium currents in gastroi...

Amberg, Gregory Charles.

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A-type potassium currents in gastrointestinal smooth muscle.

Record Type:	Electronic resources : Monograph/item
Title/Author:	A-type potassium currents in gastrointestinal smooth muscle./
Author:	Amberg, Gregory Charles.
Description:	178 p.
Notes:	Source: Dissertation Abstracts International, Volume: 63-07, Section: B, page: 3091.
Contained By:	Dissertation Abstracts International63-07B.
Subject:	Biology, Animal Physiology. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3060369
ISBN:	0493759271

A-type potassium currents in gastrointestinal smooth muscle.
Amberg, Gregory Charles.

A-type potassium currents in gastrointestinal smooth muscle. - 178 p.

Source: Dissertation Abstracts International, Volume: 63-07, Section: B, page: 3091.

Thesis (Ph.D.)--University of Nevada, Reno, 2002.

Outward currents through potassium (K+) channels are the primary means by which excitable cells oppose membrane excitability. In smooth muscles, diverse patterns of electrical activity are determined to a large extent by the complement of K+ currents present. The K+ currents present in the smooth muscle syncytium accomplish this by modulating responses from pacemaker and neural inputs. Transient outward, or "A-type" currents are voltage-dependent K+ currents that possess rapid activating and inactivating kinetics and usually become available at negative potentials.

ISBN: 0493759271Subjects--Topical Terms:

1017835
Biology, Animal Physiology.

A-type potassium currents in gastrointestinal smooth muscle.
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020 $a 0493759271
035 $a (UnM)AAI3060369
035 $a AAI3060369
040 $a UnM $c UnM
100 1 $a Amberg, Gregory Charles. $3 1907217
245 1 0 $a A-type potassium currents in gastrointestinal smooth muscle.
300 $a 178 p.
500 $a Source: Dissertation Abstracts International, Volume: 63-07, Section: B, page: 3091.
500 $a Adviser: Kenton M. Sanders.
502 $a Thesis (Ph.D.)--University of Nevada, Reno, 2002.
520 $a Outward currents through potassium (K+) channels are the primary means by which excitable cells oppose membrane excitability. In smooth muscles, diverse patterns of electrical activity are determined to a large extent by the complement of K+ currents present. The K+ currents present in the smooth muscle syncytium accomplish this by modulating responses from pacemaker and neural inputs. Transient outward, or "A-type" currents are voltage-dependent K+ currents that possess rapid activating and inactivating kinetics and usually become available at negative potentials.
520 $a Although commonly associated with neuronal cell-types, A-type currents have been identified in smooth muscles, including those of the gastrointestinal (GI) tract. Murine fundic, antral, and colonic smooth muscle cells possess robust A-type K+ currents. A smaller A-type current is detected in jejunal myocytes. The kinetic and pharmacological properties of these currents suggest that Kv4 (Shal) channels are the principle underlying molecular entity. This suggestion has been confirmed using molecular techniques, which indicate that Kv4.2 and Kv4.3 are the primary mediators of A-type currents in smooth muscle cells throughout the murine GI tract. Additionally, in the colon and jejunum, A-type current densities parallel the expression of K + channel interacting proteins (KChIPs). These proteins belong to a family of Kv4-specific auxiliary subunits that impart substantial influence over functional expression of these channels.
520 $a The A-type current in murine colonic myocytes is regulated in a calcium-dependent manner by calcium-calmodulin-dependent protein kinase II and by the phosphatase calcineurin. Kinase activity is associated with a slowing of inactivation while phosphatase activity has the reciprocal effect. This slowing of inactivation functionally transforms an inactivating A-type current into a slowly inactivating delayed rectifier potassium current. In doing so, the sustained component of this current is enhanced.
520 $a A-type currents make significant contributions toward the resting membrane potential of several GI smooth muscles. This conclusion is supported by experimental evidence in intact tissue preparations and in isolated smooth muscle cells. In this respect, the A-type currents in GI smooth muscles are assuming a role not traditionally assigned to a rapidly inactivating current. However, the observation of distinct sustained A-type current components under steady-state conditions lends support to this conclusion.
590 $a School code: 0139.
650 4 $a Biology, Animal Physiology. $3 1017835
690 $a 0433
710 2 0 $a University of Nevada, Reno. $3 626634
773 0 $t Dissertation Abstracts International $g 63-07B.
790 1 0 $a Sanders, Kenton M., $e advisor
790 $a 0139
791 $a Ph.D.
792 $a 2002
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3060369