Actions of manganese ions in contraction of smooth muscle.
1. Manganese ions (Mn2+) have been used in the last few decades as one of a number of inorganic Ca2+ channel blockers to investigate Ca2+ channels in excitable smooth muscle cells. 2. It has been recently reported that in addition to its inhibitory effects on the Ca2+ channels, Mn2+ in millimolar concentrations also produces contraction in the state of cell membrane depolarization. 3. Mn2+ has been shown to be able to permeate the cells via voltage-operated L-type Ca2+ channels in the membranes and directly activates contractile proteins in smooth muscles. 4. Intracellular sites of action have been proposed for Mn2+ in smooth muscles.
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Department of Veterinary Pharmacology, Faculty of Agriculture, Yamaguchi University, Japan.
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008345:Manganese / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology
D015220:Calcium Channels; D008345:Manganese