1991 Nobel Prize in Physiology or Medicine
Reason for Award
for their discoveries concerning the function of single ion channels in cells
Laureates
Germany
Germany
Explanation
On the surface of every cell in our body there are many tiny “doors.” These doors are called ion channels, and when they open, tiny electrical particles called ions move through. Mr. Neher and Mr. Sakmann used an extremely thin glass tube to measure the tiny electric current that flows when just one door opens. Thanks to their work, we now understand better how the heart beats and how the brain sends signals. Their discovery also helps scientists design new medicines.
Related Keywords
ion channel
Ion channels are membrane-spanning proteins that selectively allow specific ions to cross the lipid bilayer. Their opening and closing occur within sub-millisecond time frames and regulate membrane potential and intracellular signaling. Numerous subtypes—such as sodium, calcium, and chloride channels—possess distinct gating mechanisms and pharmacological profiles. Channel dysfunction leads to disorders like arrhythmia and epilepsy, making them prime drug targets. Observation at the single-channel level was made possible by Neher and Sakmann’s work.
patch-clamp technique
The patch-clamp technique uses a glass pipette to gently suck a small patch of membrane, forming a high-resistance gigaseal for low-noise current recordings. Configurations such as whole-cell or inside-out enable detailed analysis of ion-channel behavior. Its key advantage is direct visualization of quantized single-channel current steps. Modern adaptations include automated planar-chip systems that allow high-throughput screening. It is now an indispensable standard in pharmacology, toxicity testing, and basic research.
membrane potential
Membrane potential is the voltage difference across the cell membrane created by unequal ion distributions. The resting potential is largely determined by potassium permeability and can be approximated by the Goldman equation. When ion channels open, transient changes in membrane potential generate action potentials and trigger signaling cascades. Patch-clamp allows investigators to clamp this voltage while measuring current, a powerful approach for dissecting voltage-dependent channel function. Dysregulation of membrane potential underlies excitotoxicity and metabolic disorders.
synaptic transmission
Synaptic transmission is the process of information transfer at synapses, with ion channels playing a central role. An action potential opens voltage-gated Ca²⁺ channels at the terminal, and incoming calcium triggers vesicle fusion. Released neurotransmitters bind ligand-gated ion channels or GPCRs on the postsynaptic cell, producing an electrical response. Patch-clamp can record postsynaptic currents with millisecond resolution, testing predictions of quantal release models. Disrupted synaptic transmission contributes to depression, schizophrenia, and Alzheimer’s disease.
action potential
An action potential is a rapid change in membrane potential seen in nerves and muscles. Opening of voltage-gated Na⁺ channels produces the upstroke, while subsequent K⁺ channel opening repolarizes the membrane. Single-channel recordings have revealed probability distributions of channel opening during this event. The speed and frequency of action potentials directly influence information coding, and channel blockers are clinically employed to treat pain and arrhythmias. Hodgkin-Huxley equations remain the classic framework for modeling action potentials.
electrophysiology
Electrophysiology is the study of electrical phenomena in living systems. Its measurement range spans from ECGs and EEGs down to single-ion-channel recordings. Thanks to Neher and Sakmann’s breakthrough, molecular-scale data can now be directly compared with tissue-level behavior. Modern electrophysiology integrates optogenetics and high-density microelectrode arrays to enhance spatial and temporal resolution. Applications are expanding into disease diagnostics and neuro-engineering.