| Popis: |
There are many advantages, when studying the molecular basis of transmitter function, to select a hypertrophied system which utilizes a single transmitter. The use of adrenal medullary cells as models for adrenergic nerve terminals is well known. For the investigation of cholinergic function we have used the electromotor neurones of Torpedo marmorata (Whittaker and Zimmermann, 1976; Whittaker and Stadler, 1980). The cholinergic electrocytes of the electric organ of this fish are derived embryologically from muscle (Fox and Richardson, 1979). Each fish provides 0.4 — 0.5 kg of electric tissue with a nerve-terminal content 500 — 1000 times greater than that of muscle. Preparations of small (so-called T-sacs; Dowdall and Zimmermann, 1977), large (Morel, Israel, Manaranche and Mastour-Franchon, 1977) and improved (Richardson and Whittaker, 1981) cholinergic synaptosomes, presynaptic plasma membranes (Stadler and Tashiro, 1979) and synaptic vesicles (Sheridan and Whittaker, 1964; Whittaker, Essman and Dowe, 1972; Ohsawa, Dowe and Whittaker, 1979; Tashiro and Stadler, 1978) can all be readily obtained. |
