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1. Post-synaptic responses to acetylcholine (ACh) released from nerve terminals and from iontophoretic micropipettes were investigated in skeletal muscle fibres of the snake. Each fibre has a compact end-plate consisting of fifty to seventy synaptic boutons. The fibres were voltage clamped, and synaptic currents were recorded from visually identified(More)
1. Synaptic transmission was studied in visually identified parasympathetic ganglion cells that modulate the heart beat of the mudpuppy Necturus maculosus).2. The brief pulse of acetylcholine (ACh) released from terminals of the vagus nerve after each impulse can produce two distinct post-synaptic responses in individual principal cells of the ganglion: (i)(More)
A search was made in sympathetic ganglia of the bullfrog for a noncholinergic, nonaminergic transmitter that is released by a distinct group of preganglionic axons. These initiate a late slow excitatory postsynaptic potential which lasts for many minutes. The most promising candidate for the role of transmitter is a peptide that resembles luteinizing(More)
SUMMARY This account deals with studies of slow synaptic potentials, a new pep-tidergic transmitter, and integrative mechanisms at synapses in vertebrate autonomic ganglia. In neurones of the cardiac parasympathetic ganglia of the mudpuppy (Necturus maculosus) both rapid excitatory and slow inhibitory synaptic potentials interact. The same transmitter,(More)
We previously proposed that, in sympathetic ganglia of the bullfrog, a peptide which resembles luteinizing hormone-releasing factor (LH-RF, luliberin) functions as the transmitter for the late slow excitatory postsynaptic potential (epsp), a signal that may last 5-10 min. To test this hypothesis further, we have compared the physiological andpharmacological(More)
1. The sensitivity of the subsynaptic membrane of twitch muscles of the frog and snake to iontophoretically applied acetylcholine (ACh) was determined. Optimal placement of ACh micropipettes on to the postsynaptic membrane resulted in potentials that were similar, though not identical, to the miniature excitatory post-synaptic potentials (min e.p.s.p.s). A(More)
A single-electrode voltage clamp was used to study the slow muscarinic and late slow peptidergic excitatory post-synaptic currents (e.p.s.c.s) in B cells of the paravertebral sympathetic ganglia of the bull-frog. Conductance decreases were measured during peptidergic e.p.s.c.s in nearly all cells at clamped potentials near the resting level. In about half(More)
1. The distribution of acetylcholine (ACh) sensitivity was mapped in skeletal twitch muscles of the snake, frog and mudpuppy with iontophoretic methods that provide a resolution in the mum range. 2. The preparations were thin sheets of muscle fibres that were viewed with Nomarski optics, giving sharp definition of cellular detail. The muscles in the snake(More)
1. Postsynaptic responses to acetylcholine released from nerve terminals and from iontophoretic micropipettes were investigated in skeletal twitch-muscle fibers of the snake. The preparation consists of thin sheets of muscle fibers in which details of the end plate, including the outlines of individual synaptic boutons, are clearly seen in the living state.(More)