Basic biological research with the striated muscle by using cryotechniques and electron microscopy.
Several basic mechanisms underlying living phenomena are not really understood. Unequivocal interpretations of data concerning the following phenomena--to name but a few--are missing: cellular accumulation of potassium; cellular exclusion of sodium, cell volume regulation, shape change of cells (e.g. of muscle cells during contraction), electrical potential differences between inside and outside of living cells. The theoretical treatment of these phenomena as found in all current textbooks is based on the membrane-pump theory (MPT) with the following essential features. The bulk of the main cellular cation K+ is freely dissolved in free cellular water and membrane-situated pumps are responsible for the high level of K+ and the low level of Na+ found in virtually all living cells. On the other hand, the above mentioned phenomena are explained by the association-induction hypothesis (AIH) without the proposal of membrane-situated pumps and with the postulations of selective K+ adsorption to cellular proteins and of a specific cell water structure which has a low solvency for Na+ and other solutes. Experimental findings are reviewed which contradict the MPT and support the AIH. In addition, electron microscopic experiments with cryoprocessed striated muscle are reviewed which establish cellular K+ binding (adsorption) and a cellular water structure which is different from that of normal free water. Cryoexperiments with the striated muscle and model systems are proposed which may help to obtain further information on the specific interactions between proteins, ions, and water in living cells.