Inhibitory effect of lithium on muscle contractions caused by various stimulants in guinea-pig ileum

Inhibition by cations of antagonist binding to histamine H1‐receptors: differential effect of sodium ions on the binding of two radioligands

“…The accessibility or otherwise from the extracellular medium of the site for the cations other than Na+ is also uncertain. The IC50 for Li' inhibition of histamine-induced contraction of guinea-pig intestinal muscle strips, measured in the presence of approximately 140mM Na+, is 44mM (Hori et al, 1989), which is close to the IC50for inhibition of [3H]-QMDP binding, 39mm (Table 1). However, the IC50 values for Li+ against carbachol-and K+-induced contraction of the muscle strips were also in the range of 4045 mM and the degree of inhibition correlated well with the concentration of intracellularly accumulated Li+, which appeared to have direct effects on the contractile proteins (Hori et al, 1989).…”

“…The IC50 for Li' inhibition of histamine-induced contraction of guinea-pig intestinal muscle strips, measured in the presence of approximately 140mM Na+, is 44mM (Hori et al, 1989), which is close to the IC50for inhibition of [3H]-QMDP binding, 39mm (Table 1). However, the IC50 values for Li+ against carbachol-and K+-induced contraction of the muscle strips were also in the range of 4045 mM and the degree of inhibition correlated well with the concentration of intracellularly accumulated Li+, which appeared to have direct effects on the contractile proteins (Hori et al, 1989). Clearly, evaluation of the inhibitory effects of ions on tissue responses remote from receptor activation presents difficulties, particularly with the divalent cations such as Ni2+ which are also channel blockers.…”

The Inhibitory Effect of Li+ on Contractile Elements of Intestinal Smooth Muscle

“…in 30-60 min (8) and the inhibitory effect increased with the accumulation of Li+ in the cell (9)(10)(11). Recently, we have reported that Li+-induced relaxation is not due to a decrease in cytosolic Ca 2+ level ([Ca2+];) and that Li+ relaxes Ca 2+-induced contraction in permeabilized tissue (11). The purpose of the present experiments is to further clarify the mechanism for the inhibitory effect of Li+ in guinea pig ileal smooth muscle.…”

“…Treatment of guinea pig ileal muscle with 68.4 mM Li+ solution increased the cellular Li+ content to 10-20 mmol/kg wet wt. in 30-60 min (8) and the inhibitory effect increased with the accumulation of Li+ in the cell (9)(10)(11). Recently, we have reported that Li+-induced relaxation is not due to a decrease in cytosolic Ca 2+ level ([Ca2+];) and that Li+ relaxes Ca 2+-induced contraction in permeabilized tissue (11).…”

Proceedings of the Physiological Society, 25‐26 March 1991, University College of London Meeting: Communications

“…This effect is thought to be the basis of the depressant action of LiCI on agonist-induced contraction in smooth muscle. However, Hori et al (1989) recently showed that LiCl reduced the Ca-sensitivity of smooth muscle contractile proteins. The purpose ofthis study was to study these two effects in a-toxin-permeabilized strips of rat anococcygeus muscle (100 pm diameter).…”