Contractility relationship

The mechanical behavior of the contractile apparatus of smooth muscle is also very similar to that of striated muscle. So that to the extent that the force-velocity curves reflect the interaction of mechanical force and the rate of enzymatic catalysis, the steps of the chemomechanical transduction cycles in the two muscles are apparently modulated in similar ways. Also relationships between the active isometric force and muscle length are very similar (except as noted above for shorter lengths). 

Webb, S.C., Fleetwcxjd, G. and Montgomery, R. (1983). Absence of a relationship between extracellular potassium accumulation and contractile failure in the ischaemic or hypoxic rabbit heart. J. Mol. Cell. Cardiol. 15, 27. 

Herrera MD, Zarzuelo A, Jimenez J, Marhuenda E, Duarte J. 1996. Effects of flavonoids on rat aortic smooth muscle contractility structure-activity relationships. Gen Pharmacol 27 273-277. 

Most members of the imidazolylphenylpyridazinone series have been found to produce dose-related increases in myocardial contractility that were associated with minor increases in heart rate and decreases in systemic arterial blood pressure. Studies of structure-activity relationships in this class have been published [25-27]. 

Bengel FM, Permanetter B, Ungerer M, Nekolla SG, Schwaiger M. Relationship between altered sympathetic innervation, oxidative metabolism and contractile function in the cardiomyopathic human heart a non-invasive study using positron emission tomography. Eur Heart J 2001 22 1594-1600... 

The development of synchrotron radiation as a source for x-ray diffraction and the investigation of the structure and contractile mechanism of insect flight muscle have had a symbiotic relationship since the early 1970 s. While it is perhaps true that, until a few years ago, synchrotrcm radiation research had benefitted more from this than insect flight muscle research, recent time-resolved work has begun to fulfill the promise of those first diffraction experiments carried out by Rosenbaum et al. (1971) in 1970. 

D. Sarsero, P. Molenaar, A.J. Kaumann, N.S. Freestone, Putative /t4-adrenoceptors in rat ventricle mediate increases in contractile force and cell Ca2-i- Comparison with atrial receptors and relationship to (-)-[3H]-CGP 12177 binding, Br. J. Pharmacol. 128(1999) 1445-1460. 

It is believed that fine cytoplasmic arms connect the nuclei-containing portion of the myocytons with the contractile components such that many parenchymal cells are in fact myocytons (Lumsden and Hildreth, 1983). Also, some cytoplasmic arms are believed to form multiple neuromuscular junctions that provide for neuronal control/modulation of muscle activity. Limited information is available on the functional relationship of trematode nerve and muscle although the situation in ces-todes has been described as polyneuronal and polyterminal in that each neuron can form synapse-like contacts with multiple myocytons and each myocyton can synapse with several neurons (Webb, 1987). Morphologically atypical synapses and paracrine release sites have been described in the relationship between muscle and nerve in flatworms details on the role they play are not available, although they are believed to facilitate nerve-muscle communication. 

Cardiac dilatation and hypertrophy — taking advantage of the Frank-Starling relationship to utilize more contractile elements. 

The relationship of intracellular sodium to intracellular calcium is such that a very small increase in sodium in terms of percentage increase leads to a disproportionately large increase in calcium. Therefore, a direct effect on the sodium/potassium-ATPase to inhibit sodium pump activity is the primary mechanism of the positive inotropic effect of the cardiac glycosides, while secondary elevation of intracellular calcium provides the ionic punch to increase contractility. A diagram of the relationship between sodium/potassium-ATPase and calcium is shown in Figure 12.6. 

The HICS document reflects the same basic principles of command and control, chain of command, predefined positions, established reporting and communication relationships, use of common nomenclature, expandability and contractility of the scale of the operation, and span of control, as did its predecessor HEICS. 

Buck ED, Lachnit WG, and Pessah IN (1999) Mechanisms of delta-hexachlorocyclohexane toxicity I. Relationship between altered ventricular myocyte contractility and ryanodine receptor function. Journal of Pharmacology and Experimental Therapeutics 289(1) 477 85. de Oliveira RM, Bastos LH, de Oliveira e Dias AE, da Silva SA, and Moreira JC (2003) Residual concentration of hexachlorocyclohexane in a contaminated site in Cidade dos Meninos, Duque de Caxias, Rio de Janeiro, Brazil, after calcium oxide treatment. Cad Saude Publica 19(2) 447-453. 

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