Changes in [Mg2+] a millimolar range have significant inverse effect on the Ca2+- (or Sr2+)activated tension generation of skeletal muscle fibers. Single frog (Rana pipiens) semitendinosus fibers were "skinned" (sarcolemma removed) and contracted isometrically bathing solutions varying [Ca2+] or [Sr2+] but constant pH, [MgATP2-], [K+], [CP2-], [CPK], ionic strength. Sr2+-)activated steady-state tensions recorded for three [Mg2+]'s: 5 X 10(-5)M, 1 10(-3) M, 2 M; these expressed as percentages...

The maximal calcium-activated isometric tension produced by a skinned frog single muscle fiber falls off as the ionic strength of solution bathing this is elevated declining to zero near 0.5 M varied using KCl. When other neutral salts are used, always declines at high strength, but there some difference between various used. anions and cations can be ordered in terms their ability inhibit tension. order increasing inhibition (decreasing tension) for propionate(-) approximately SO(4) (--) <...

1. Maximum and submaximum Ca‐activated tension in mechanically disrupted rat ventricular fibres was examined solutions containing 30 micron, 100 micron 4 mM‐MgATP either 50 or 1 mM ionized Mg. 2. In the absence of added Ca, significant amounts base‐line (up to 50% maximum) develop less than micron‐MgATP. This effect is Mg‐dependent; more produced with micron‐Mg mM. 3. Increasing MgATP concentration shifts pCa‐% maximum relationship direction increasing Ca required for activation. At pCa...

Single muscle fibers from rabbit soleus and adductor magnus semitendinosus muscles were peeled to remove the sarcolemma then stimulated release Ca2+ by (a) caffeine application or (b) ionic depolarization accomplished via substitution of choline chloride for potassium propionate at constant [K+] X [Cl-] in bathing solution. Each stimulus, caffeine, elicited an isometric tension transient that appeared be due released sarcoplasmic reticulum (SR). The peak magnitude (Cl- -induced) increased...

Excitation-contraction coupling in skeletal muscle is known to be under absolute control of plasmalemma voltage, but the steps from transverse (T)-tubule depolarization Ca2+ release sarcoplasmic reticulum have not been elucidated. The effect changing T-tubule membrane potential on inositol 1,4,5-trisphosphate (InsP3) stimulation was studied explore a possible role for InsP3 as chemical signal excitation-contraction coupling. microinjected into peeled rabbit fibers at pipette concentration...

Many theorists of the ‘political turn’ in animal rights theory emphasize need for animals’ interests to be considered political decision-making processes, but deny that this requires self-representation and participation by animals themselves. I argue domesticated co-authoring our shared world is indeed required, explore two ways proceed: 1) enabling voice within existing geography human-animal roles relationships; 2) freeing into a revitalized public commons (‘animal agora’) where citizens...

Submaximum and maximum forces of the cardiac muscle contractile apparatus, activated by Ca2+ or Sr2+, were determined as a function Mg2+ concentration. Apical left ventricular tissue from Sprague-Dawley rats was broken homogenization into small bundles fibers with disrupted sarcolemmas (skinned). Tension generation graded according to concentration Sr2+ in solutions bathing skinned measured photodiode force transducer. Steady-state tensions for various levels activation at each four...

Abstract Many commentators—including some animal rights theorists—have argued that non-human animals cannot be seen as members of the demos because they lack critical capacities for self-rule and moral agency which are required citizenship. We argue this worry is based on mistaken ideas about both citizenship, one hand, animals, other. Citizenship requires self-restraint responsiveness to shared norms, but these should not understood in an unduly intellectualized or idealized way. Recent...

Gestational diabetes mellitus (GDM) is a serious complication of pregnancy associated with increased risk adverse outcomes for both mother and infant. This study assesses the association maternal exercise during GDM selected infant GDM-related outcomes. The analysis uses information derived from 1988 National Maternal Infant Health Survey (NMIHS) data.Women in NMIHS database were identified grouped as to having experienced non-GDM (n = 2,952,482) or 105,600) pregnancy. Non-GDM groups...