Abstract
We have investigated the active, passive and myogenic tension-internal circumference relations of rat intramural coronary and, as controls, mesenteric small arteries (internal diameter ca. 200 μm) using an isometric myograph. The active tensions of the vessels (when fully activated with 30 μM serotonin in K-saline) reached a maximum (2.54 N/m, coronary; 3.39 N/m, mesenteric) at an internal circumference, L0, where the passive tensions (measured in Ca-free solution) were 0.80 N/m (coronary) and 0.74 N/m (mesenteric). Below 0.8 L0 and above 1.2 L0 the active tensions fell linearly, the zero tension intercepts being 0.37 L0 and 1.74 L0 (coronary) and 0.40 L0 and 1.72 L0 (mesenteric). The passive wall tensions of the vessels rose exponentially as a function of internal circumference, the wall tension at 1.5 L0 being 10.0 N/m (coronary) and 8.5 N/m (mesenteric). In normal physiological salt solution, the coronary vessels had a Ca2+ dependent myogenic tone which was also dependent on the internal circumference. Maximum myogenic tone (0.54 N/m) was obtained at 1.18 L0. The mesenteric vessels had no such myogenic tone. Histological examination showed that the media/lumen ratios of both vessel types were the same, and that the smooth muscle content of the media was greater in the coronary (81%) than in the mesenteric (72%) vessels. The smaller active tension of the coronary vessels could not therefore be ascribed to a reduced smooth muscle content, but possibly in part to an observed heterogeneous arrangement of the smooth muscle cells in the coronary vessels.
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References
Ashton FT, Somlyo AV, Somlyo AP (1975) The contractile apparatus of vascular smooth muscle: Intermediate high voltage stereo electron microscopy. J Mol Biol 98:17–29
Brayden JE, Halpern W, Brann LR (1983) Biochemical and mechanical properties of resistance arteries from normotensive and hypertensive rats. Hypertension 5:17–25
Cox RH (1982) Mechanical properties of the coronary vascular wall and the contractile process. In: Kalsner S (ed) The coronary artery. Croom Helm London, pp 59–90
De Mey J, Brutsaert DL (1984) Mechanical properties of resting and active isolated coronary arteries. Circ Res 55:1–9
Dobrin PB (1978) Mechanical properties of arteries. Physiol Rev 58:397–460
Downey, JM (1982) The extravascular coronary resistance. In: Kalsner S (ed) The coronary artery. Croom Helm, London, pp 268–291
Fay FS (1976) Mechanical properties of single isolated smooth muscle cells. In: Worcel M, Vassort G (eds) Smooth muscle pharmacology and physiology, vol 50. Inst Natl Santé Recherce Medicale (INSERM) Paris, pp 327–342
Feigl E (1983) Coronary physiology. Physiol Rev 63:1–205
Gordon AM, Huxley AF, Julian FG (1966) The variation in isometric tension with sarcomere length in vertebrate muscle fibres. J Physiol (Lond) 184:170–192
Grayson J (1982) Functional morphology of the coronary circulation. In: Kalsner S (ed) The coronary artery. Croon Helm, London, pp 343–364
Harder DR (1984) Pressure-dependent membrane depolarization in cat middle cerebral artery. Circ Res 55:197–202
Harder DR, Belardinelli L, Sperelakis N, Rubio R, Berne RM (1979) Differential effects of adenosine and nitroglycerin on the action potentials of large and small coronary arteries. Circ Res 44:176–182
Herlihy JT, Murphy RA (1973) Length-tension relationship of smooth muscle of the hog carotid artery. Circ Res 33:275–283
Johnson PS (1980) The myogenic response. In: Bohr DF, Somlyo AP, Sparks HV (eds) The cardiovascular system, Handbook of physiology, sec 2. Williams and Wilkins, Baltimore, pp 402–442
Mulvany MJ (1986) Role of vascular structure in blood pressure development of the spontaneously hypertensive rat. J Hypertension 4 (Suppl 3) S61-S63
Mulvany MJ, Halpern W (1976) Mechanical properties of vascular smooth muscle in situ. Nature 260:617–619
Mulvany MJ, Halpern W (1977) Contractile properties of small arterial resistance vessels in spontaneously hypertensive and normotensive rats. Circ Res 41:19–26
Mulvany MJ, Nyborg N (1980) An increased calcium sensitivity in mesenteric resistance vessels from young and adult spontaneously hypertensive rats. Br J Pharmacol 71:585–596
Mulvany MJ, Warshaw W (1979) The active tension-length curve of vascular smooth muscle related to its cellular components. J Gen Physiol 74:85–104
Mulvany MJ, Hansen PK, Aalkjær C (1978) Direct evidence that the greater contractility of resistance vessels in spontaneously hypertensive rats is associated with narrowed lumen, a thickened media, and an increased number of smooth muscle cell layers. Circ Res 43:854–864
Murphy RA (1980) Mechanics of vascular smooth muscle. In: Bohr DF, Somlyo AP, Sparks HV (eds) Handbook of physiology. Williams and Wilkins, Baltimore, pp 325–352
Nyborg NCB (1985) Effects of calcium antagonists on resistance vessels. A dihydropyridine derivative, BAY K 8644, with agonistic properties on isolated coronary resistance vessels from WKY rats. Adv Appl Microcirc 8:53–58
Nyborg NCB, Mikkelsen EO (1985) In vitro study on the response to noradrenaline, serotonin, and potassium of intramyocardial and mesenteric resistance vessels from Wistar rats. J Cardiovasc Pharmacol 7:417–423
Osol G, Halpern W (1985) Synthetic arterial natriuretic factor does not dilate small arteries from the rat. (Abstract 669) Fed Proc 44:1555
Parrat JR (1982) Myocardial metabolic activity as a determinant of coronary vessel tone. In: Kalsner S (ed) The coronary artery. Croom Helm, London, pp 309–342
Peterson, JW, Paul JP (1974) Effects of initial length and active shortening on vascular smooth muscle contractility. Am J Physiol 227:1019–1024
Speden RN (1960) The effect of initial strip length on the noradrenaline-induced isometric contraction of arterial strips. J Physiol 154:15–25
Sperelakis N (1982) Electrophysiology of vascular smooth muscle of the coronary artery. In: Kalsner S (ed) The coronary artery. Croom Helm, London, pp 118–167
Toma BS, Wangler RD, De Witt DF, Sparks HV (1985) Effect of development on coronary vasodilator reserve in isolated guinea pig heart. Circ Res 57:538–544
Van Dijk AM, Wieringa PA, Vaan Meer M, Laird JD (1984) Mechanics of resting isolated single vascular smooth muscle cells from bovine coronary artery. Am J Physiol 246:C277–C287
Vatner SF, Murray PA (1982) Reflex control of coronary arteries. In: Kalsner S (ed) The coronary artery. Croom Helm, London, pp 216–238
Wilcken DEL (1982) Myogenic factors in the determination of coronary vascular resistance. In: Kalsner S (ed) The coronary artery. Croom Helm, London, pp 292–308
Zelcer E, Sperelakis N (1982) Spontaneous electrical activity in pressurized small mesenteric arteries. Blood Vessels 19:301–310
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Nyborg, N.C.B., Baandrup, U., Mikkelsen, E.O. et al. Active, passive and myogenic characteristics of isolated rat intramural coronary resistance arteries. Pflugers Arch. 410, 664–670 (1987). https://doi.org/10.1007/BF00581329
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DOI: https://doi.org/10.1007/BF00581329