Stjarne: The present review puts the emphasis on two important developments: the discovery that individual postganglionic sympathetic neurons may secrete multiple transmitter substances from different classes of vesicles and by different mechanisms, and the introduction of new techniques which may permit for the first time direct impulse by impulse analysis of transmitter secretion in individual sympathetic nerve varicosities. Illes: Exogenous and endogen opioid peptides elicit a number of effects in the organism, usually by modifying the function of transmitter and hormone systems, for example, activation of multiple opioid receptors. The effects of opioids on transmitter and hormone release have frequently been reviewed. This review gives a detailed overview on the involvement of multiple opioid receptors in these processes. Rothstein: This article gives an overview of the exchange in acidification and transepithelial salt and water transfer in nonepithelial cells. Delineating the exchanger's most important, common features, and concentrating particularly on its role in cell pH and volume regulation.

The First International Symposium on the Metabolic Interconversion of Enzymes was held in Santa Margherita Ligure, Italy, in May, 1970, under the direction of Professor G. Bonsignore. Because of rapid developments in this field, a second Symposium was organized a year and a half later in Rottach-Egern, Germany (October, 1971) by Professors E. He1mreich, H. Holzer and O. Wieland. At that time, so much new information had accumulated that it was decided to repeat such conferences approx imately every other year; the United States was chosen as the next site. This publi cation reports the Proceedings of the Third International Symposium on the Metabolic Interconversion of Enzymes held at the Battelle Seattle Research Center, Seattle, Washington, June 5 - 8, 1973. The conferences were originally designed to examine the control of metabolic reactions by covalent modification of certain key enzymes. Covalent, as opposed to allosteric or metabolic, regulation had first been recognized some fifteen years be fore. Initially thought to represent an added sophistication in regulatory processes possibly reserved to higher organisms, covalent regulation has now been found in both prokaryotes and eukaryotes. Those early studies in covalent modification revealed for the first time the existence of special "converter" enzymes whose purpose in life is to switch other molecules from one state of activity to another."

This book is a compilation of formal presentations made during a three-day invitational conference at Battelle Research Center in Seattle, Washington. The purpose of organizing and publishing the proceedings of the conference is to provide a comprehensive survey of present knowledge on the determinants of membrane structure, the molec ular specificity of membrane function, and the dynamic properties of membranes. Each presentation was followed by discussions which, be cause of their informal and spontaneous character, have not been in cluded in this publication. Molecular studies of biological membrane phenomena have progressed over the past decade to the point where it is now realistic to expect future resolution of the physico-chemical processes or forces governing the organization, function, and dynamic properties of membranes. Drs. Radda, Kaback, and Schwyzer, each presenting a different approach to the biochemical and biophysical study of membranes, devoted four to six weeks as Battelle Visiting Fellows to developing the format and the roster of participants of the conference. The scientific "cluster" concept for planning the conference is reflected in the breadth of topics presented in this publication."