The Third International Symposium on Excitation-Contraction Coupling in Skeletal, Cardiac, and Smooth Muscle, organized by George Frank, C. Paul Bianchi, and Henk E. DJ. ter Keurs, was held in Banff Centre, Banff, Alberta, Canada during June 26 to June 30, 1991. The theme of these symposia has been to recognize the similarities and dissimilarities of excitation-contraction coupling in skeletal, cardiac, and smooth muscle. Cross fertilization of concepts of excitation-contraction coupling in these three types of muscle has occurred since the early studies in the late fifties and early sixties on skeletal muscle. Investigators in each field meet only at specialized symposia which exclude investigators in the other fields. The purpose of the symposia has been to bring together international investigators studying excitation-contraction coupling in skeletal, cardiac, and smooth muscle so that we may learn from each other and hence provide a more global concept of excitation-contraction. The Third International Symposia has accomplished its objective as we recognize that calcium channels of the sarcolemma and the sarcoplasmic reticulum play key essential roles in excitation-contraction coupling in all three types of muscles. In skeletal muscle the recognition that E-C coupling consists of two parallel mechanisms, one dependent upon a dihydropyridine voltage-sensitive sensors coupled to calcium release from the terminal cisternae via the ryanodine sensitive channel in the foot structure of the triad.

Knowledge of the mechanism of action of drugs at cellular, subcellular, or molecular levels is of vital importance not only in giving the basis of inter pretation of the systemic action of drugs but also in improving existing drugs; in designing new forms of drugs; and in giving the basis of therapeutic applications. Classical pharmacology, concerning the action of drugs at integrated levels, does not necessarily give sufficient information as to the mechanism of action of drugs. A variety of sophisticated concepts utilizing the methods of physics, chemistry, biophysics, biochemistry, and physiology must be synthesized to understand the mechanism of action. Only since the last decade, however, have these techniques been fully applied to pharma cological investigations. It is of utmost importance to realize that a new dimension of pharmacological research has indeed emerged as a result of such a multidisciplinary approach; this approach is encompassed in general and cellular pharmacology. Such recent studies of drug actions have led to a number of important findings. Certain chemicals and drugs were found to possess highly specific actions on cellular functions, so that they are widely being used as powerful tools for the study of a variety of physiological and pharmacological prob lems. Our knowledge of the cellular mechanisms of drug action has provided the basis for interpreting the systemic effects of the drugs and insight into the molecular mechanism involved.