Summary
Electrophysiological evidence is presented that at least 30 percent of sartorius muscle fibres of adult frogs are innervated by two or more axons at a single end-plate zone. In these fibres, increasing stimulation of the common sartorius nerve led to the appearance of two or more distinct levels of end-plate potentials (e.p.p.) (or currents, measured by the voltage clamp technique). They had an identical time course, reversal potential and delay to nerve stimulation. When the recording microelectrode was moved along the same fibre and reinserted, both components of e.p.p. decreased proportionally. This indicated that both components of e.p.p. originated very closely to each other on the muscle fibre, presumably in one end-plate zone. Many fibres of the sartorius muscle of adult frogs therefore possess polyneural innervation of a single end-plate zone, which is otherwise typical for early stages of ontogenesis.
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BENNETT, M.R., PETTIGREW, A.G.: The formation of synapses in amphibian striated muscle during development. J. Physiol.252, 203–239 (1975)
BENOIT, P., CHANGEUX, J.P.: Consequences of tenotomy on the evolution of multiinnervation in developing rat soleus muscle. Brain Res.99, 354–358 (1975)
DREYER, F., PEPER, K.: A monolayer preparation of innervated skeletal muscle fibres of the m. cutaneus pectoris of the frog. Pflügers Arch.348, 257–268 (1974)
BROWN, M.C., JANSEN, J.K.S., VAN ESSEN, D.: Polyneural innervation of skeletal muscle in new-born rats and its elimination during maturation. J. Physiol.261, 387–422 (1976)
KATZ, B., KUFFLER, S.W.: Multiple motor innervation of the frog s sartorius muscle. J. Neurophysiol.4, 209–223 (1941)
KATZ, B., MILEDI, R.: The binding of acetylcholine to receptors and its removal from the synaptic cleft. J. Physiol.231, 549–574 (1973)
KÖLLIKER, A.: Untersuchen über die letzten Endingungen der Nerven. Mit 4 Kupfertafeln. Z. wiss. Zool.XII, 149–164 (1863)
Miledi, R.: From Nerve to Muscle. Discovery (London), October (1961)
REDFERN, P.A.: Neuromuscular trans-mission in new-born rats. J. Physiol.209, 701–709 (1970)
TAKEUCHI, A., TAKEUCHI, N.: Active phase of frog s end-plate potential. J. Neurophysiol.22, 395–411 (1959)
TERENTJEV, P.V.: “The Frog”, Nauka, Moscow, pp. 59–69 (in Russian) (1950)
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Vyskočil, F., Magazanik, L.G. Dual end-plate potentials at the single neuromuscular junction of the adult frog. Pflugers Arch. 368, 271–273 (1977). https://doi.org/10.1007/BF00585207
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DOI: https://doi.org/10.1007/BF00585207