Title : Inhibition of calcium-dependent ATPase from sarcoplasmic reticulum by a new class of indolizidine alkaloids, pumiliotoxins A, B, and 251D - Tamburini_1981_J.Neurochem_37_775 |
Author(s) : Tamburini R , Albuquerque EX , Daly JW , Kauffman FC |
Ref : Journal of Neurochemistry , 37 :775 , 1981 |
Abstract :
Pumiliotoxins (PTX) A, B, and 251D, members of a new class of indolizidine alkaloids isolated from the skin of poison frogs of the family Dendrobatidae, inhibit Ca2+-ATPase activity in sarcoplasmic reticulum vesicles from frog and rat hind-limb muscles. PTX-B and PTX-A appear to be relatively specific inhibitors of Ca2+-ATPase; PTX-A is much less potent than PTX-B. PTX-251D is a potent inhibitor of Ca2+-ATPase, and was also found to inhibit Na+, K+, and Mg2+-ATPases in rat brain synaptosomes. Caffeine and verapamil, two drugs known to affect calcium translocation, are very weak inhibitors of the Ca2+-ATPase. The Ki values for inhibition of the Ca2+-ATPase of rat and frog sarcoplasmic reticulum by PTX-B were comparable and ranged between 22 and 36 microM. Inhibition of calcium-dependent ATPase in sarcoplasmic reticulum by pumiliotoxin-B is noncompetitive with calcium and is not readily reversible. Based on structure-activity profiles, it is concluded that inhibition of Ca2+-ATPase by the indolizidine alkaloids is responsible for the alkaloid-elicited prolongation of twitch in intact muscle. |
PubMedSearch : Tamburini_1981_J.Neurochem_37_775 |
PubMedID: 6456330 |
Tamburini R, Albuquerque EX, Daly JW, Kauffman FC (1981)
Inhibition of calcium-dependent ATPase from sarcoplasmic reticulum by a new class of indolizidine alkaloids, pumiliotoxins A, B, and 251D
Journal of Neurochemistry
37 :775
Tamburini R, Albuquerque EX, Daly JW, Kauffman FC (1981)
Journal of Neurochemistry
37 :775