Бюллетень сибирской медицины (Dec 2014)
THE ROLE OF GASOTRANSMITTERS IN REGULATING OF THE FUNCTIONS OF SMOOTH MUSCLES: THE POSSIBLE EFFECTOR SYSTEMS
Abstract
Influence of gasotransmitters carbon monoxide (CO) and hydrogen sulfide (H2S) on the electrical and contractile activities of smooth muscle cells (SMCs) of the guinea pig ureter and rat aorta were studied by methods of double sucrose bridge and mechanography. It has been shown that CO causes a dose-dependent decrease of the contractile response of SMCs of the ureter and rat aorta and also reduces the amplitude and duration of the action potential plateau. Against the background of the action of biologically active substances, agonists α1-adrenergetic and H1-histaminergetic receptors (phenylephrine and histamine, respectively), these effects of CO donor (CORM II) were amplified. The inhibitory effect of CO on the parameters of the contractile and electrical activities of smooth muscles is attenuated by blocking potassium channels of plasma membrane with tetraethylammonium (TEA) or inhibition of soluble guanylate cyclase (ODQ [1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-l-one]). Thus, the effects of carbon monoxide on the electrical and contractile activities of SMCs are associated with an increase potassium conductivity of the membrane or the activation of soluble guanylate cyclase.In experiments with a donor of hydrogen sulfide (NaHS), it was shown, that it has an activating effect on the electrical and contractile activities of smooth muscles of the guinea pig ureter, which is caused by the action of potassium conductivity of the membrane. Activating effect of H2S on the contractile properties of SMCs of the guinea pig ureter decreased by blocking ATP-dependent channels with glibenclamide. Analysis of the effect of H2S on sodium and calcium conductance of the membrane smooth muscles of the ureter using modified sodium-free and TEA- containing Krebs solution showed that the contribution of potassium conductance is mainly sold at high concentrations (100 and 1000 μmol) donor NaHS. Probably, that the impact of low concentrations of NaHS (10 μmol) on the amplitude of contractions SMCs of the ureter and performed through the activation of the calcium component of the action potential. It was shown, that activating effect of NaHS determined by involving sodium-dependent ion transporters to cAMP-dependent inhibition of potassium conductance membranes of smooth muscles.
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