Nick A Lavidis

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The embryonic period of motoneuron programmed cell death (PCD) is marked by transient motor axon branching, but the role of neuromuscular synapses in regulating motoneuron number and axonal branching is not known. Here, we test whether neuromuscular synapses are required for the quantitative association between reduced skeletal muscle contraction, increased(More)
The secretion of a quantum by groups of release sites (me) along the length of nerve terminal branches has been studied with extracellular electrodes at mature and juvenile toad neuromuscular junctions. The position of the recording sites with respect to the terminal branches was determined following zinc-iodide staining of terminals. me declined with(More)
P2X1-type purinoceptors have been shown to mediate fast transmission between sympathetic varicosities and smooth muscle cells in the mouse vas deferens but the spatial organization of these receptors on the smooth muscle cells remains inconclusive. Voltage clamp techniques were used to estimate the amplitudes of spontaneous excitatory junction currents(More)
The number of quanta secreted from release sites along visualized terminal branches at toad (Bufo marinus) neuromuscular junctions during different seasons was determined. Terminal branches were visualized by prior staining with the fluorescent dye, 3,3'-diethyloxadicarbocyanine iodide (DiOC2(5)). The average number of quanta secreted by release sites and(More)
The rat lateral gastrocnemius muscle receives a topographical projection from lumbar segmental nerves L4 and L5. A study has been made of the development of this projection during the period when polyneuronal innervation is eliminated. The tetanic contraction due to stimulation of each nerve was compared with that due to stimulation of both nerves(More)
The pattern of innervation of three muscles from rat (lateral gastrocnemius, biceps brachii, pectoralis minor) has been ascertained in the neonatal period (birth to 4 days) and from two to three weeks postnatal. Contraction, electrophysiological and histological methods were used to determine the pattern of innervation. There is a change in the segmental(More)
1. The number of quanta secreted from visualized release sites along terminal branches at toad (Bufo marinus) neuromuscular junctions in different extracellular concentrations of calcium ions. [Ca2+]o, and during facilitation was determined. Terminal branches were visualized by prior staining with the fluorescent dye, 3-3 diethyloxardicarbocyanine iodide(More)
A study has been made of the effects of calcium ions on the number of quanta secreted from all the release sites at an amphibian motor nerve terminal recorded with an intracellular microelectrode (m) compared with the number secreted simultaneously from a small number of release sites recorded with an extracellular microelectrode (me). If the endplate(More)
beta2-Laminin is important for the formation of neuromuscular junctions in vertebrates. Previously, we have inactivated the gene that encodes for beta2-laminin in mice and observed predominantly prejunctional structural defects. In this study, we have used both intra- and extracellular recording methods to investigate evoked neurotransmission in(More)
ATP released by sympathetic varicosities of the mouse vas deferens binds to P2X receptors which activate fast, ligand-gated channels, resulting in depolarisation of smooth muscle cells. We examined the development of fast neuromuscular transmission at surface longitudinal smooth muscle fibres of the mouse vas deferens. Sympathetic varicosities were(More)