Effects of mercuric ions on isolated guinea-pig ileum.
The possible physiological significance of low concentrations of Hg2+ in the guinea-pig ileum has been investigated. Responses to nerve stimulation by single electrical shocks, acetylcholine (ACh), and histamine (Hi) and the response to ACh of a depolarized preparation were examined. A stimulant effect of Hg2+, in the concentration range of 10 nM-1 microM, dominated in intestine accommodated in biological saline solution. This excitatory effect was probably mainly due to stimulation of a depolarization-coupled initiation of the contraction. The inhibitory effect of Hg2+, 10 nM-1 microM, observed in depolarized muscle was presumably due to a decreased Ca2+ availability for the contractile process. In the higher concentration range, 1-100 microM, a probably direct action on the contractile elements causing irreversible deterioration of the preparation seems to be present.
Moberg
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D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects / Q000502:physiology; D008297:Male; D008628:Mercury / Q000494:pharmacology*; D008954:Models, Biological; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D009599:Nitroprusside; D006632:Histamine; D014700:Verapamil; D008628:Mercury; D000109:Acetylcholine