Organelles and Neuromuscular Activity
IN THE FOREGOING CHAPTERS ORGANELLES HAVE BEEN DISCUSSED MAINLY IN terms of their intracellular roles. However, some organelles have functions that reach beyond the boundaries of the cell. In particular, it seems that in the evolution of multicellular organisms, the ER and Golgi systems have extended their spheres of influence and acquired specialized functions that are vital to the coordination of the organism. This is shown in the production and secretion of insulin via the ER-Golgi-vesicle system of the cells of the pancreas; similarly thyroxine, oxytocin and other polypeptide hormones that regulate the physiology of organs and organisms are secreted from their sites of synthesis by vesicles that appear to be a simple extension of the primitive function of ER and Golgi bodies, i.e. to deliver membrane material to the cell surface. Rapid internal communication and responsive reflex action are brought about by the neuromuscular system, the activity of which is also dependent on specialized cell organelles that are associated with ER and Golgi bodies, namely the synaptic vesicles of neurones and the sarcoplasmic reticulum of muscle. These organelles, together with the chromaffin granules of adrenal medulla, are intrinsically interesting, central to an understanding of neurophysiology, and demonstrate specialization of organelles in the service of communication between tissues.
KeywordsSarcoplasmic Reticulum Synaptic Vesicle Adrenal Medulla Golgi Body Presynaptic Membrane
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- Ingebretsen, O. C. & Flatmark, T. (1979) Active and passive transport of dopamine into chromaffin granule ghosts isolated from bovine adrenal medulla. J. Biol. Chem. 254, 3833–3837.Google Scholar
- Johnson, R. G. & Scarpa, A. (1979) Protonmotive force and catecholamine transport in silated chromaffin granules. J. Biol. Chem. 254, 3750–3760.Google Scholar
- Katz, B. (1969) The Release of Neural Transmitter Substance. Liverpool University Press, Liverpool.Google Scholar
- Osborne, M. P. (1977) Role of vesicles with some observations on vertebrate sensory cells. In Synapses (Eds. Cottrell, G. A. & Usherwood, P. N. R.). pp. 40-63. Blackie, Glasgow & London.Google Scholar
- Marchbanks, R. M. (1977) Turnover and release of acetylcholine. In Synapses, pp. 81–102 (eds. Cottrell, G. A. & Usherwood, P. N. R.) Blackie, Glasgow and London.Google Scholar
- Tauc, L. (1977) Transmitter release at cholinergic synapses. In Synapses, pp. 64–80 (Eds. Cottrell, G. A. & Usherwood, P. N. R.) Blackie, Glasgow and London.Google Scholar
- Weiner, N. (1979) Multiple factors regulating the release of norepinephrine consequent to nerve stimulation. Fed. Proc. 38, 2193–2202.Google Scholar
- Pette, D. & Heilmann, C. (1979) Some characteristics of sarcoplasmic reticulum in fast- and slow-twitch muscles. Biochem. Soc. Trans. 7, 765–767.Google Scholar