Influence of calixarene C-99 on contractile activity of rat large intestine smooth muscles

Abstract

The regularities of influence of new high-affinity inhibitor of plasma membrane sodium pump calixarene C-99 on the contractile activity of rat’s large intestine circular smooth muscle were studied. It was found that under preliminary complete blockage of the sodium pump using ouabain (100 µM) the calixarene C-99 (100 µM) causes activation of smooth muscles spontaneous contractions. It has been also found that under ouabain preliminary action the calixarene changes mechanokinetical parameters of contractile responses to depolarization of smooth muscle cells plasma membranes via potassium solution (80 mM), as well as per application of the muscarinic acetylcholine agonist (10 µM). It has been shown that calixarene C-99 has no effect on the Ca2+ mobilization from the sarcoplasmic reticulum. Thus, the calixarene C-99 action on intestinal smooth muscles is not limited to the plasma membrane’s sodium pump blocking. Possible mechanisms of action calixarenes C-99 on smooth muscle’s contractile activity are discussed.

Keywords

• smooth muscle
• calixarene C-99
• the sodium pump
• mechanokinetics
• spontaneous and induced contractions