It can be argued that nonselective cation channels were the first sort of ion channel to be described, though the word channel was not used at the time. Their existence was implied by Fatt and Katz in 1952, when they described the action of acetylcholine at the muscle endplate as producing "a large nonselective increase of ion permeability, i.e. a short circuit". Shortly afterwards, in 1956, Katz referred to "aqueous channels through which small ions can pass ... " (del Castillo and Katz, Prog. Biophysics and Biophys. Chern. 6, 121-170). Now, more than thirty years later, it has become clear that there are far more types of nonselective cation channels than anyone could have imagined a few years ago, and that they are found in a vast range of tissues. One has, of course, become quite accustomed to such diversity in, for example, GABA receptors, but this is not quite the same thing. A In the case of GABAA receptor we are talking about a fairly narrow range of structural diversity (resulting largely from differences in subunit composition) within a single type of channel with more-or-Iess well defined function. In the case of nonselective cation channels the function is often not known, and relatively few have been cloned. It seems certain though, that they encompass a wide range of quite different structural types.

Inhalt
Nonselective Cation Channels.- Nonselective Cation Channels: Physiological and Pharmacological Modulations of Channel Activity.- Receptor-Activated Nonselective Cation Channels.- Structure, Diversity, and Ionic Permeability of Neuronal and Muscle Acetylcholine Receptors.- AMPA-Type Glutamate Receptors Nonselective Cationic Channels Mediating Fast Excitatory Transmission in the CNS.- Mechanically Sensitive Cation Channels.- Mechanically Sensitive, Nonselective Cation Channels.- Stretch-Activated Nonselective Cation Channels in Urinary Bladder Myocytes: Importance for Pacemaker Potentials and Myogenic Response.- Mechanosensitive Nonselective Cation Channels in the Antiluminal Membrane of Cerebral Capillaries (Blood-Brain Barrier).- Gap Junction Channels.- The Gap Junction Channel.- Cyclic Nucleotide-Activated Nonselective Cation Channels.- Cyclic Nucleotide-Gated Nonselective Cation Channels: A Multifunctional Gene Family.- Cyclic AMP-Gated Cation Channels of Olfactory Receptor Neurons.- Renal Epithelial Cells Show Nonselective Cation Channel Activity and Express a Gene Related to the cGMP-Gated Photoreceptor Channel.- Ciliary Cation Conductances in Olfactory Receptor Cells of the Clawed Toad Xenopus laevis.- Nonselective Cation Channels Activated by Intracellular Calcium.- Control of Cell Function by Neuronal Calcium-Activated Nonselective (CAN) Cation Channels.- Nonselective Cation Channels in Exocrine Gland Cells.- Nonselective Cation Channels in Brown and White Fat Cells.- Inhibitors of Nonselective Cation Channels in Cells of the Blood-Brain Barrier.- Nonselective Cation Channels in Cells of the Crypt-Base of Rat Distal Colon.- Nonselective Cation Channels as Regulatory Components of Cells from Various Tissues.- Poorly Selective Cation Channels in ApicalMembranes of Epithelia.- Nonselective Cation Channels in Cardiac and Smooth Muscle Cells.- Physiology of Muscarinic Receptor-Operated Nonselective Cation Channels in Guinea-Pig Ileal Smooth Muscle.- Nonselective Ion Pathways in Human Endothelial Cells.- Properties and Regulation of Human Platelet Cation Channels.- The Role of a PDGF-Activated Nonselective Cation Channel in the Proliferative Response.- Cation Channels in Oocytes and Early States of Development: A Novel Type of Nonselective Cation Channel Activated by Adrenaline in a Clonal Mesoderm-Like Cell Line (MES-1).- Slowly-Activating Cation Channels in the Vacuolar Membrane of Plants.