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The storage of ACH in presynaptic nerve endings.
Whittaker, V. P
Gilliland, Ian C
Dr V.P. Whittaker lectures on the storage of ACH (acetylcholine) in presynaptic nerve terminals.
Segment 1 Dr Gilliland introduces Dr Whittaker, who begins the lecture. Whittaker begins by describing the synapses in the nervous system and how they are arranged. He also discusses chemical transmission in the nervous system and the synapses' vulnerabilities. He begins to explain how many hallucinogenic drugs and tranquilisers are chemical analogues of central transmitters. Time start: 00:00:00:00 Time end: 00:04:50:01 Length: 00:04:50:01 Segment 2 Whittaker continues to talk about drugs that act on the nervous system. The formula of the transmitter dopamine is shown, as well as the hallucinogen mescaline's formula. He points out the similarities. Another slide shows the transmitter 5-hydroxytryptamine and the hallucinogen LSD - again they share commonalities. A third slide compares acetylcholine and atropine. He then discusses his work on the way acetylcholine is stored in nerve terminals, first explaining what acetylcholine is and how it works. A picture of an elasmobranchii (a flatfish) is seen, which has a high acetylcholine content. Whittaker discusses this and other species of fish and how they are used in research. Time start: 00:04:50:01 Time end: 00:10:35:00 Length: 00:05:44:24 Segment 3 Electron micrographs show the nerve endings of the fish, and Whittaker describes them and where they occur. He then talks about the problem of breaking down the electric tissue in order to isolate the vesicles. A fragment of electroplaque is shown, and Whittaker points out the badly damaged external nerve membrane. An enlarged picture is also seen. Whittaker describes how to prepare vesicles using the electroplaque fragments. Time start: 00:10:35:00 Time end: 00:15:51:00 Length: 00:05:16:00 Segment 4 A series of graphs shows the make-up of separated, centrifuged vescicles. Whittaker discusses the results of an electron microscope examination of the separation and the distribution of the various enzymes and transmitters. Time start: 00:15:51:00 Time end: 00:20:30:20 Length: 00:04:39:20 Segment 5 Whittaker continues to discuss the centrifuged vescicles and the distribution of the enzymes and transmitters. A set of figures shows concentrations in the vescicles, and he talks about acetylcholine in particular. He also talks about vesiculin, a protein found in the vesicle preparation. Another diagram shows the gel elution pattern obtained when vesicles are suspended in water and in isosmotic sucrose, and Whittaker explains this comparison. He then discusses a preparation of vesiculin involving dialysis and freeze-drying. A graph shows the results of this experiment. Time start: 00:20:30:20 Time end: 00:25:08:00 Length: 00:04:37:05 Segment 6 Whittaker continues to explain the freeze-dried preparation experiment, discussing data in graphs shown on screen. He also talks about the amino acid composition of vesiculin. Time start: 00:25:08:00 Time end: 00:30:03:00 Length: 00:04:56:00 Segment 7 Next, Whittaker talks about the role of vesiculin in the cholinergic vesicle. He discusses how it might act as an ion exchange resin. He also talks about a possible carrier system existing within the wall of the vesicle, shown in a diagram. He concludes the lecture by saying how research into proteins and acetylcholine storage could benefit botulism and myasthenia gravis treatment. Time start: 00:30:03:00 Time end: 00:34:18:07 Length: 00:04:15:07
Presented by Dr V.P. Whittaker, Department of Biochemistry, University of Cambridge. Introduced by Dr Ian Gilliland. Made by University of London Audio-Visual Centre for the Postgraduate Medical Federation, University of London. Produced by Peter Bowen.
This video is one of around 310 titles, originally broadcast on Channel 7 of the ILEA closed-circuit television network, given to Wellcome Trust from the University of London Audio-Visual Centre shortly after it closed in the late 1980s. Although some of these programmes might now seem rather out-dated, they probably represent the largest and most diversified body of medical video produced in any British university at this time, and give a comprehensive and fascinating view of the state of medical and surgical research and practice in the 1970s and 1980s, thus constituting a contemporary medical-historical archive of great interest. The lectures mostly take place in a small and intimate studio setting and are often face-to-face. The lecturers use a wide variety of resources to illustrate their points, including film clips, slides, graphs, animated diagrams, charts and tables as well as 3-dimensional models and display boards with movable pieces. Some of the lecturers are telegenic while some are clearly less comfortable about being recorded; all are experts in their field and show great enthusiasm to share both the latest research and the historical context of their specialist areas.
The scientific basis of medicine