In this volume of Reviews of Physiology, Biochemistry and Pharmacology there a contributions by M.D. Swope, E. Lolis, F.Hofmann, L. Lacinova, N. Klugbauer, M. Hermann, P. Berger, S.S. Shen, J.S. Kim, M.E. Weksler, M. Hirsch-Kauffmann and M.Schweiger.

R. Levenson: Isoforms of the Na,K-ATPase: Family Members in Search of Function.- E. Petzinger: Transport of Organic Anions in the Liver. An Update on Bile Acid, Fatty Acid, Monocarboxylate, Anionic Amino Acid, Cholephilic Organic Anion and Anionic Drug Transport.- E. Schultz, K.M. McCormick: Skeletal Muscle Satellite Cells.

This special volume provides up-to-date information on research dealing with the regulation of the biosynthesis and degradation of cyclic GMP and with the regulation of physiological systems by cyclic GMP. The publication of this volume could not have come at a more appropriate time, with significant work in this area having led to our current understanding of the role of nitric oxide in signal transduction, and the 1998 Nobel Prize in Medicine and Physiology for Furchgott, Murad and Ignarro. Moreover, the introduction in early 1998 of sildenafil (Viagra), a selective inhibitor of a cyclic GMP phosphodiesterase, for the treatment of erectile dysfunction in men represents the first successful therapeutic application of an agent designed to alter the activity of a molecular target in a cyclic GMP pathway.

K.W. Bock: The Aryl Hydrocarbon or Dioxin Receptor: Biologic and Toxic Responses.- K. Grieshaber, I. Hardewig, U. Kreutzer, and H.-O. Poertner: Physiological and Metabolic Responses to Hypoxia in Invertebrates.- K.-W. Koch: Calcium as Modulator of Phototransduction in Vertebrate Photoreceptor Cells.

P.J. Pearson, P.M. Vanhoutte: Vasodilator and Vasoconstrictor Substances Produced by the Endothelium. L. Dux: Muscle Relaxation and Sarcoplasmic Reticulum Function in Different Muscle Types. C.C. Ashley, P.J. Griffith, T.J. Lea, I.P. Mulligan, R.e. Palmer, and S.J. Simnett: Barnacle Muscle: Ca2+ Activation and Mechanics.

J.A. Roth: Membrane-Bound Catechol-O-Methyltreansferase: A Reevaluation of Its Role in the O-Methylation of the Catecholamine Transmitters. D.J. Benos, S. Cunningham, R.R. Baker, K.B. Beason, Y. Oh, and P.R. Smith: Molecular Characteristics of Amiloride-Sensitive Sodium Channels. D. Pette and G. Vrbov : Adaptation of Mammalian Skeletal Muscle Fibers to Chronic Electrical Stimulation.

In this regular issue of Reviews of Physiology the first contribution by Warth and Bleich is on K+ Channels and Colonic Function, the second by Offermanns on Mammalian G-Protein Function in vivo: New Insights Through Altered Expression, and the third contribution by Tenenholz et al. (including one editor of the series) on Structural Determinants of Scorpion Toxin Affinity: The Charybdotoxin (alpha-KTX) Family of K+-channel Blocking Peptides.

In this second special issue on signal transduction leading specialists in their fields again present overviews of topics related to the highly topicalsubject of signal transduction. The first contribution, by Keppler, deals with the biosynthesis, transport, inactivation, and analysis of leukotrienes. Mohr et al. present an excellent overview of the biology of the peptide hormone oxytocin and its role in signal transduction.The review by Holzer describes the significance of peptinergic sensory neurons in the control of vascular functions. In the contribution by Wolf etal the molecular biology of the Y chromosome is discussed.

Cook et al.: Phospholipases C and D in Mitogenic Signal Transduction. Moolenaar et al: Lysophosphatidatic Acid: A Bioactive Phospholipid with Growth Factor-Like Properties. Kozma et al.: Serine/Threonine Kinases in thePropagation of the Early Mitogenic Response. Diringer et al: A Retrospective on Transformation, Growth Control, and some Peculiarities of Lipid Metabolism. Villereal et al.: Calcium Signals in Growth Factor Signal Transduction. Wakabayashi et al.: Structure Function of the Growth Factor-Activatable Na+/H+ Exchanger. Herrlich et al.: DNA Damage-Induces Gene Expression: Signal Transduction and Relation to Growth Factor Signaling. Lucibello et al.: Transcription Factor Encoding Oncogenes

W. Ulbricht: Effects of veratridine on sodium currents and fluxes. W. Meyerhof: The elucidation of somatostatin receptor functions: a current view.M. Leist, F. Gantner, g. Kunstle and A. Wendel: Cytokine-mediated hepatic apoptosis.

Special Issue on the Tird Filament System

The objectives in this special issue are (1) to critically review current information on the mechanisms coupling extracellular regulatory signals to regulation of cross-bridge cycling and proliferation in smooth muscle, and (2) identify significant gaps or unresolved issues that are important topics for future research. The experimental and analytical difficulties discussed above are increasingly recognized and surmounted. Elucidation of the molecular and cellular events underlying the biologal properties of smooth muscle is in the midst of a period of rapid progress. While the reviews reveal many gaps to be filled and illustrate areas of contention, they also capture the excitement of new discoveries.

In this volume of Reviews of Physiology, Biochemistry and Pharmacology there a contributions by M.D. Swope, E. Lolis, F.Hofmann, L. Lacinova, N. Klugbauer, M. Hermann, P. Berger, S.S. Shen, J.S. Kim, M.E. Weksler, M. Hirsch-Kauffmann and M. Schweiger.