LABORATORY AND BRANCH RESEARCH REVIEWS 75Laboratory of Biophysics, NINDB
The second to last laboratory to be created within the NIMH-NINDB
intramural basic research program was the NINDB-supported Laboratory
of Biophysics, headed by Kenneth S. Cole, in early 1954. The Laboratory
of Biophysics expanded on earlier work on the instantaneous conductivity
of the nerve fiber during activity to the study of how ionic movements
initiate and propagate the nerve impulse, both normally as well as under
the influence of drugs and disease.^1 Specifically, it set up–via computers–
complex mathematical theories in an attempt to predict the formation
and behavior of the nerve impulse under various normal and pathological
conditions, predictions which were then experimentally tested against a
simple nerve fiber of a squid giant axon.^2
The squid giant axon provided the first, direct measurement of the
ionic movements responsible for excitation and propagation of a nerve
impulse through a nerve membrane.^3 A voltage clamp allowed for the
characteristics of these ion movements to be accurately, quickly, and reli
ably obtained.^4 Improved methods and techniques also allowed for the
measurement of radioactive tracer fluxes during times of principal ionic
current flows across the squid axon membranes.^5
Some of the specific studies conducted within this laboratory involv
ed: 1) investigating the action of synthetic cholinesterase inhibitors and
their correlation with nerve action; 2) studying the effects of stereo-
specifically tailored amino alcohol derivatives on the electrical activity
of the single node in terms of threshold and action current parameters;
3) generating mathematical models for ionic permeability of the nodal
membrane; 4) studying the effect of temperature rises on the speed of
sodium and potassium processes and peak conductances; 5) assessing the
effects of external calcium and magnesium ions; and 6) comparing the
resting and action potentials of squid and lobster giant axons.^6