Unformatted text preview: um channel into 2 types (one activated by large depolarization-high v,
another small depolar-small v). high v activated diverge to L type and
non-L (L refer to liver)-important in heart. calcium channels arose through
evolution of 2 rounds of gene duplication from one domain of potassium
channel. the calcium and sodium have in common very large subunit
called alpha subunit that is consist of convalently-link domains of ancestral
calcium channel appear first evolutionary. they rapidly differentiated into 2
type: the high V open by large depolarization, and low V one. the one
we're talking the most about is the highV activated Ca which found in liver
and other tissue (non-L). L-type calcium channel (or known as
dihydropyridine-sensitive calcium channel) is important in cardiac muscle
that are responsible for main inward current cardiac action potential.
channels are often identify by specific ligands which may be inhibitors or
stimulators, here's there's a specifiic class of inhibitors called is recently evolve (last).
dihydropyridine that bind to L-Type calcium channels. dihydropyridine is
used to treat disease related to functioning of L-type channel and heart
(high blood pressure) KV = V-gated K+ channels
CaV = V-gated Ca2+ channels
L-type are dihydropyridine-sensitive
HVA = high-voltage activated
LVA = low-voltage activated
NaV = V-gated Na+ channels voltage ion channel (opening of gate is control by membrane potential) evolved: there's common structure between vertebraes. in mammals the inwardly rectifying
potassium channel (is very important, see star)
-there's great diversity of ion channel. most of potassium channels that are volatege-gated at rest. when depolarize they open. there's at least 2 major type: type
open rapidly upon depolarization, one open more slowly. there's also potassium channels that close slowly and other close rapidly. there are potassium channels
that are not only voltage-gated and also activated by increases in intracellular calcium ion.
***-all potassium channels have common structure and open with depol...
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- Spring '09