Английская Википедия:Isopimaric acid

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Isopimaric acid (IPA) is a toxin which acts as a large conductance Ca2+-activated K+ channel (BK channel) opener.

Sources

IPA originates from many sorts of trees, especially conifers.[1]

Chemistry

IPA is one of the members of the resin acid group and it is a tricyclic diterpene.[1]

Target

IPA acts on the large-conductance calcium activated K+ channels (BK channels).[2][3]

Mode of action

BK channels are formed by α subunits and accessory β subunits arranged in tetramers. The α subunit forms the ion conduction pore and the β subunit contributes to channel gating. IPA interaction with the BK channel enhances Ca2+ and / or voltage sensitivity of the α subunit of BK channels without affecting the channel conductance. In this state BK channels can still be inhibited by one of their inhibitors, like charybdotoxin (CTX).[2][3] Opening of the BK channel leads to an increased K+-efflux which hyperpolarizes the resting membrane potential, reducing the excitability of the cell in which the BK-channel is expressed.

Toxicity

Studies on rainbow trout hepatocytes have shown that IPA increases intracellular calcium release, leading to a disturbance in the calcium homeostasis. This could be important in the possible toxicity of the toxin.

See also

Notes

Шаблон:Reflist

References

Шаблон:Toxins Шаблон:Ion channel modulators