Accumulation of Acetylcholine Receptors at Nerve-Muscle Contacts in Culture

Cohen, Maxime C.; Anderson, M J; Zorychta, E.; Weldon, P.R.

doi:10.1016/s0079-6123(08)64645-2

Cited by 33 publications

(18 citation statements)

References 48 publications

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“…According to the binomial law, the probability of this outcome is <0.0001. A similarly high coincidence of nerve endings and receptor clusters has been noted in Xenopus neural tube-myocyte co-cultures (Cohen and Wilson, 1985). Other studies have shown that growth cones can release ACh even before they contact target myotubes (Hume et al, 1983;Young and Poo, 1983).…”

Section: Discussionsupporting

confidence: 55%

The distribution of acetylcholine receptor clusters and sites of transmitter release along chick ciliary ganglion neurite-myotube contacts in culture.

Role¹,

Roufa²,

Fischbach³

1987

The Journal of Cell Biology

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Abstract. Acetylcholine receptors accumulate along the length of cholinergic neuron-skeletal muscle contacts in vitro. The main purpose of this study was to describe, in a quantitative way, the distribution of acetylcholine receptor clusters induced by ciliary ganglion neurons over a period of time extending from hours to weeks after contacts are established. Neurites were filled with Lucifer Yellow and receptor clusters were identified with rhodamine-bungarotoxin. A cluster located within 5 gm of a nerve process or I0 l~m of the base of a growth cone was considered to be a neuriteassociated receptor patch (NARP). The first synaptic potentials were evoked 20 min after growth cone-myotube contact, and, after 24 h of co-culture, >60% of the nerve-muscle pairs tested were functionally connected. NARPs appear rapidly; the first clusters were detected "o6 h after the neurons were plated. They were composed of several small subclusters or speckles of rhodamine-bungarotoxin fluorescence. The initial accumulation of receptors may occur at the advancing tips of nerve processes because NARPs were found at >80 % of the growth cone-muscle contacts examined between 12 and 24 h of co-culture. Over the 3-wk period examined, the mean incidence of NARPs ranged between 1.0 and 2.6 per 100 gm of neurite-myotube contact, with the peak observed on the second day of co-culture. During the first 3 d in culture, when the neurons were multipolar, nearly all of the primary processes induced one or more clusters. With time, as the neurons become unipolar (Role and Fischbach, 1987) NARPs persisted along the remaining dominant process. Measurements made during the third day of co-culture suggest that NARPs disappear along shorter neurites before they retract. Synaptic currents were detected by focal extracellular recording at 55 % of the NARPs. The fact that spontaneous or evoked responses were not recorded at 45 % suggests that contacts with clusters exhibit two functional states. Two types of presynaptic specialization at identified NARPs observed by scanning electron microscopy appear to be correlated with the functional state.MBRYONIC motoneurons promote the accumulation of acetylcholine (ACh) I receptors (AChRs) at newly formed nerve-muscle junctions in vivo and in vitro Cohen, 1980;Steinbach and Bloch, 1986;Schuetze and Role, 1987). In chick cultures, it is clear that receptors accumulate soon after nerve-muscle contact is established, and that each neuron is capable of inducing more than one receptor cluster (Frank and Fischbach, 1979;Role et al., 1985). However, little information is available 1. Abbreviations used in this paper: ACh, acetylcholine; AChR, acetylcholine receptor; NARP(s), neurite-associated receptor patch(es); R-BTX, rhodamine-conjugated alpha-bungarotoxin.Portions of this work have appeared in abstract form (1982. Soc. Neurosci.

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Section: Discussionsupporting

confidence: 55%

The distribution of acetylcholine receptor clusters and sites of transmitter release along chick ciliary ganglion neurite-myotube contacts in culture.

Role¹,

Roufa²,

Fischbach³

1987

The Journal of Cell Biology

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“…10, 1992 A cardinal event in neuromuscular synaptogenesis is the aggregation of ACh receptors (AChRs) in the newly forming postsynaptic membrane. This aggregation is nerve induced, and it begins within a few hours at sites where growing axons contact embryonic muscle cells Cohen et al, 1979;Frank and Fischbach, 1979;Chow and Cohen, 1983). Current evidence indicates that agrin, or a closely related molecule, is the neuronal agent that triggers this aggregation ofAChRs at the developing neuromuscular junction (McMahan and Wallace, 1989;Wallace, 199 1).…”

Section: Antibodiesmentioning

confidence: 99%

Early appearance of and neuronal contribution to agrin-like molecules at embryonic frog nerve-muscle synapses formed in culture

Cohen

Godfrey

1992

J. Neurosci.

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Antibodies against chicken and Torpedo agrin were used for immunofluorescent staining in order to assess the spatial distribution and temporal appearance of agrin-like molecules at newly formed synaptic contacts in cultures of embryonic Xenopus nerve and muscle cells. The antibodies stained Xenopus neuromuscular junctions and removed ACh receptor (AChR)-aggregating activity from extracts of Xenopus brain. Immunofluorescence was observed at almost all nerve- induced AChR aggregates, even at microaggregates in cocultures as young as 7.5 hr and at nerve-muscle contacts less than 2 hr old. Microdeposits of immunofluorescence extended as far distally as, or farther than, the microaggregates of AChRs along young nerve-muscle contacts. They also occurred along portions of growing neurites that were not in contact with muscle. By contrast, immunofluorescence was rarely observed at the nonsynaptic aggregates of AChRs that form on noninnervated muscle cells. These results raise the possibility that neuronally derived microaggregates of agrin-like molecules may be primary sites of nerve-induced clustering of AChRs, and they indicate that these molecules are present at embryonic nerve-muscle synapses from the very onset of AChR aggregation. The cellular origin of the agrin-like molecules at synapses was examined in cross-species cocultures in which the neurons and muscle cells were obtained from embryos of Xenopus laevis and Rana pipiens. Immunofluorescent staining with anti-agrin antibodies reactive at both Rana and Xenopus neuromuscular junctions revealed immunofluorescence at AChR aggregates along nerve-muscle contacts involving both cross-species combinations. Immunofluorescent staining with an anti-agrin antibody reactive at Rana but not at Xenopus neuromuscular junctions was positive only at cross- species nerve-muscle contacts involving Rana neurons. These results provide the first demonstration that embryonic neurons supply agrin- like molecules to the synapses they form with embryonic muscle cells.

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“…It has been found that within the adult LSO, there is a nonuniform distribution of terminal arbors from neurons in the MNTB, such that the arborization is denser in the high-frequency dorsomedial region (Glendenning et al, 1985). It will be of interest to determine the initial projection pattern of the MNTB neurons, since neuroreceptor accumulation is responsive to the presence of afferent terminals (Cohen et al, 1979;Frank and Fischbach, 1979).…”

Section: Developmental Correlatesmentioning

confidence: 99%

Development of glycine receptor distribution in the lateral superior olive of the gerbil

Sanes

Wooten

1987

J. Neurosci.

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The concentration and relative distribution of glycine receptors were determined for the gerbil lateral superior olive at several postnatal ages. Quantitative autoradiographic techniques revealed significant 3H- strychnine binding to all regions of the nucleus from 4 to 90 d. However, during the first 20 d, a nonuniform distribution of binding emerged, such that the greatest concentration of receptor was found in the high-frequency region of the nucleus. An analysis of neuron packing density showed an approximate 2-fold distribution along the same axis at all ages. This evidence is consistent with an elimination of glycine receptors in the ventral region of the lateral superior olive as maturation progresses.

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Accumulation of Acetylcholine Receptors at Nerve-Muscle Contacts in Culture

Cited by 33 publications

References 48 publications

The distribution of acetylcholine receptor clusters and sites of transmitter release along chick ciliary ganglion neurite-myotube contacts in culture.

The distribution of acetylcholine receptor clusters and sites of transmitter release along chick ciliary ganglion neurite-myotube contacts in culture.

Early appearance of and neuronal contribution to agrin-like molecules at embryonic frog nerve-muscle synapses formed in culture

Development of glycine receptor distribution in the lateral superior olive of the gerbil

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