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Action Of Heptaminol Hydrochloride On Contractile Properties In Frog Isolated Twitch Muscle Fibre, Bruno Allard, Vincent Jacquemont, Fouad Lemtiri-Chlieh, Bernard Pourrias, Oger Rougier
Action Of Heptaminol Hydrochloride On Contractile Properties In Frog Isolated Twitch Muscle Fibre, Bruno Allard, Vincent Jacquemont, Fouad Lemtiri-Chlieh, Bernard Pourrias, Oger Rougier
fouad Lemtiri-Chlieh
1 Heptaminol stopped or delayed the progressive decline in tension which characterizes the phenomenon of fatigue in frog isolated twitch muscle fibre. 2 Heptaminol had no action on the sodium, potassium and calcium voltage-dependent ionic conductances. 3 The hypothesis of an action via an internal alkalinization was tested by comparison with the action of NH4Cl. Both substances increased the tension. 4 The action of hepataminol was suppressed in sodium-free (TRIS) solution or in the presence of amiloride while the action of NH4Cl was always observed. 5 These results could be explained by a stimulation of the Na/H antiport by heptaminol.
Alternative Temporal Control Systems For Hypodermal Cell Differentiation In Caenorhabditis Elegans, Zhongchi Liu, Victor Ambros
Alternative Temporal Control Systems For Hypodermal Cell Differentiation In Caenorhabditis Elegans, Zhongchi Liu, Victor Ambros
Victor R. Ambros
Beginning of article: In certain multicellular organisms, genetic regulatory systems that specify the timing of cell division, differentiation and morpho-genesis must accommodate environmental and physiological contingencies that perturb or arrest development. For example, Caenorhabditis elegans can either develop continuously through four larval stages (L1–L4) or arrest indefinitely as a 'dauer larva' at the second larval (L2) moult, and later resume L3 and L4 development. At the larva-to-adult (L4) moult of both con-tinuous and 'post-dauer' development, hypodermal cells switch (the 'L/A switch') from a proliferating state to the terminally differentiated state. Four temporal regulators, lin-4, lin-14, lin-28 and lin-29, have been …