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Binding of [H-3] serotonin to skeletal muscle actin


Small, DH and Wurtman, RJ, Binding of [H-3] serotonin to skeletal muscle actin, Journal of Neurochemistry, 45, (3) pp. 819-824. ISSN 0022-3042 (1985) [Refereed Article]

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DOI: doi:10.1111/j.1471-4159.1985.tb04067.x


Abstract: We previously observed that the neurotransmitter 5‐hydroxytryptamine (5‐HT, serotonin) binds with high‐ and low‐affinity interactions to an actin‐like protein prepared from rat brain synaptosomes. In this study, we examined its binding to highly purified actin obtained from rabbit skeletal muscle. Monomeric G‐actin bound serotonin with high and low affinities, exhibiting equilibrium dissociation constants (KD values) of 5 × 10−5M and 4 × 10−3M, respectively. The serotonin binding site on actin was distinct from those sites previously characterized for divalent cations, nucleotides, and cytochalasin alkaloids. The binding of serotonin (1 μM) to G‐actin was increased as much as 26‐fold by divalent cations. Potassium iodine (KI) increased the affinity of G‐actin for serotonin, KD values for this binding being 3 × 10−7M and 6 × 10−5M. Serotonin bound with even higher affinity to polymerized F‐actin, with KD values of 2 × 10−8M and 2 × 10−5M. However, the total number of binding sites on F‐actin was only about 4% of the number of G‐actin. The binding of serotonin (0.1 μM) to G‐actin could be inhibited by phenothiazines (1 μM) or reserpine (10 μM), but not by classical antagonists of serotonin receptors or by drugs that release serotonin or inhibit its uptake. The binding of serotonin to actin in vivo may participate in a contractile process related to neurotransmitter release. Copyright © 1985, Wiley Blackwell. All rights reserved

Item Details

Item Type:Refereed Article
Research Division:Biomedical and Clinical Sciences
Research Group:Neurosciences
Research Field:Neurosciences not elsewhere classified
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Small, DH (Professor David Small)
ID Code:52871
Year Published:1985
Web of Science® Times Cited:11
Deposited By:Menzies Institute for Medical Research
Deposited On:2008-10-03
Last Modified:2012-02-22

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