Richard Hume Adrian, D. L. 2nd Baron Adrian of Cambridge. 16 October 1927—4 April 1995

Biographical Memoirs of Fellows of the Royal Society ◽

10.1098/rsbm.1997.0002 ◽

1997 ◽

Vol 43 ◽

pp. 15-30

Author(s):

Andrew Huxley

Keyword(s):

Education Reform ◽

Major Part ◽

Striated Muscle ◽

Surface Membrane ◽

Scientific Work ◽

Fibre Surface ◽

Electrical Behaviour ◽

Cambridge University ◽

Vice Chancellor ◽

House Of Lords

Richard Adrian was a distinguished electrophysiologist who cleared up many of the puzzles about the electrical behaviour of striated muscle. The situation in this tissue is exceptionally complex, both because the surface membrane is invaginated to form the transverse tubules, whose surface area is several times that of the fibre surface, and because substantial amounts of charge are carried across these membranes by processes connected with the turning on of contraction itself. Apart from his scientific work, he played an important part in the life of Cambridge University, as Master of Pembroke College for 11 years and as Vice-Chancellor for two. In the House of Lords, he contributed in an important way to the debates leading up to the new Act of 1986 governing experiments on living animals, and took a major part in the defence of academic freedom in the universities when it was threatened in the Education Reform Bill of 1988.

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Linear electrical properties of striated muscle fibres observed with intracellular electrodes

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1964.0030 ◽

1964 ◽

Vol 160 (978) ◽

pp. 69-123 ◽

Cited By ~ 135

Keyword(s):

Electrical Properties ◽

Striated Muscle ◽

Surface Membrane ◽

Fibre Surface ◽

Step Function ◽

Muscle Fibres ◽

Appreciable Effect ◽

Current Application ◽

Current Path ◽

Wide Range

The linear electrical properties of muscle fibres have been examined using intracellular electrodes for a. c. measurements and analyzing observations on the basis of cable theory. The measurements have covered the frequency range 1 c/s to 10 kc/s. Comparison of the theory for the circular cylindrical fibre with that for the ideal, one-dimensional cable indicates that, under the conditions of the experiments, no serious error would be introduced in the analysis by the geometrical idealization. The impedance locus for frog sartorius and crayfish limb muscle fibres deviates over a wide range of frequencies from that expected for a simple model in which the current path between the inside and the outside of the fibre consists only of a resistance and a capacitance in parallel. A good fit of the experimental results on frog fibres is obtained if the inside-outside admittance is considered to contain, in addition to the parallel elements R m = 3100 Ωcm 2 and C m = 2.6 μF/cm 2 , another path composed of a resistance R e = 330 Ωcm 2 in series with a capacitance C e = 4.1 μF/cm 2 , all referred to unit area of fibre surface. The impedance behaviour of crayfish fibres can be described by a similar model, the corresponding values being R m = 680 Ωcm 2 , C m = 3.9 μF/cm 2 , R e = 35 Ωcm 2 , C e = 17 μF/cm 2 . The response of frog fibres to a step-function current (with the points of voltage recording and current application close together) has been analyzed in terms of the above two-time constant model, and it is shown that neglecting the series resistance would have an appreciable effect on the agreement between theory and experiment only at times less than the halftime of rise of the response. The elements R m and C m are presumed to represent properties of the surface membrane of the fibre. R e and C e are thought to arise not at the surface, but to be indicative of a separate current path from the myoplasm through an intracellular system of channels to the exterior. In the case of crayfish fibres, it is possible that R e (when referred to unit volume) would be a measure of the resistivity of the interior of the channels, and C e the capacitance across the walls of the channels. In the case of frog fibres, it is suggested that the elements R e , C e arise from the properties of adjacent membranes of the triads in the sarcoplasmic reticulum . The possibility is considered that the potential difference across the capacitance C e may control the initiation of contraction.

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