Mechanokinetics and power of the spontaneous isotonic contraction of visceral smooth muscles

S. Kosterin, O. Tsymbalyuk

Abstract: The method for the mechanokinetic analysis of the spontaneous isotonic contraction-relaxation of the visceral smooth muscle was developed (using the example of the antrum of the rats). The equations for the change in the length of the muscle preparation in time, instant rate of contraction-relaxation, mechanic work, and strength of the muscle were obtained. The elaborated method was involved in the energy interpretation of the impact of acetylcholine neurotransmitter on the isotonic contraction of the smooth muscle. It was demonstrated that the following mechanokinetic and energy parameters were most sensitive to the stimulating effect of acetylcholine on the isotonic contraction of the muscle preparation: the maximal contraction velocity VC in the inflexion time point τС at the level of the contraction phase; the maximal mechanic work ΔАmax, which was completed during the time τ0 of achieving the contraction amplitude ∆Lmax; the mechanic work ΔАτС which was performed during the characteristic time τС; the maximal power of contraction Nmax at a time point τС; the averaged power of contraction Nm during the time τ0. It is assumed that the analytic method, tested in the article, may be promising for the quantitative interpretation of the effect of physical-chemical, physiologically active, and pharmacological factors on the mechanokinetics and the energetics of the smooth muscle functioning.

Series on Biomechanics, Vol.37, No.3 (2023), 43-56

Keywords: acetylcholine; Gastric smooth muscles; mechanokinetic and energetic analysis; spontaneous contractions

DOI: 10.7546/SB.07.03.2023

Date published: 2023-08-02