Local control of neurite development by nerve growth factor

Abstract

A three-chamber culture system was devised in which neurites growing from small clusters of somas of sympathetic neurons penetrated a virtually fluid-impermeable barrier; thus the local fluid environment of the distal portions of the neurites could be controlled independently of the local fluid environment of the somas and proximal portions of the neurites. Neurites regularly penetrated the barriers if a high concentration of nerve growth factor was present on both sides, but never penetrated into chambers to which no nerve growth factor had been added.After neurites crossed the barrier, local removal of nerve growth factor from the distal portions of the neurites caused the growth of these portions to stop, and they eventually appeared to degenerate even though nerve growth factor was continuously present in the chamber that contained their somas and proximal portions. In contrast, local nerve growth factor was not required at the somas and proximal portions of the neurites; many neurons survived its withdrawal provided their somas were associated with neurite bundles that crossed into a chamber containing nerve growth factor.These results show that the growth, and probably the survival, of neurites depends upon nerve growth factor in their local environment, regardless of the nerve growth factor concentrations to which other portions of the neuron are exposed. This is entirely consistent with the notion that nerve growth factor released by sympathetic target tissues promotes the establishment and maintenance of appropriate neuron-target connections during development. Several lines of evidence suggest that nerve growth factor (NGF) plays a role in the establishment of appropriate neuron-target connections in the developing sympathetic nervous system. NGF is essential for the survival of sympathetic neurons (1-5) and causes dose-dependent increases in neuronal growth (3) and differentiation (3, 5). There is evidence of its presence in sympathetic target tissues [e.g., salivary gland (6) and iris (7)] and it is transported retrograde by sympathetic axons to sympathetic ganglia (8,9). The possibility that neurites find their targets by growing preferentially up a gradient towards a source of NGF [or other substance(s) yet to be identified] has been raised in several studies. Chamley and coworkers (10, 11) cultured explants of sympathetic ganglia in liquid medium near explants of target tissues, and after a standard incubation period, the outgrowth from the ganglionic explants was usually greater towards the target than away from the target. However, the steepness of gradients that may have been set up in the liquid medium in this experiment was unknown. Also, a gradient of NGF could have caused the effect without actually influencing the direction of neurite growth. Interpreting the influence as directional implies that the growing neurites are sensitive to NGF in their local environment, and the results of this experiment can be explained without evoking a local effect of NGF on the neurites. Neurons in...

Cleavage of myelin associated glycoprotein by matrix metalloproteinases

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“…To assess the bioactivity of soluble MMP-generated MAG fragments, specifically the effects on neuronal process growth, we used Campenot chambers (Campenot, 1977).…”

The Anterograde Transport of Rabies Virus in Rat Sensory Dorsal Root Ganglia Neurons

“…The DRG cells were seeded into the inner compartment of a two-chamber cell culture system originally developed by Campenot (1977). Briefly, the system consisted of a 35 mm collagen-coated (Vitrogen 100; Collagen Corporation) plastic plate (Falcon) which was scratched in its centre with the aid of stainless steel needles, placed in a brush 0-5 mm apart.…”

“…Rabies virus infects a great variety of neuronal cell lines (Clark, 1978;Honda et al, 1984;Iwasaki & Clark, 1977;Tsiang et al, 1983a) as well as primary dissociated neuron cultures (Lycke & Tsiang, 1987;Tsiang et al, 1983aTsiang et al, , b, 1986. Whereas conventional neuronal cultures are less appropriate for the investigation of viral transport, neurons cultivated in a compartmentalized culture system as described by Campenot (1977) will demonstrate convincingly the transport of herpes simplex virus in vitro (Kristensson et al, 1986;Lycke et al, 1984;Ziegler & Herman, 1980) and the retrograde transport of both fixed and street rabies viruses in cultured rat sensory neurons (Lycke & Tsiang, 1987;Tsiang, 1988). In this system, herpes and rabies viruses were transported in a retrograde fashion with a velocity in the range of 50 mm/day (herpes virus) and 25 mm/day (rabies virus) (Lycke et al, 1984;Lycke & Tsiang, 1987).…”

Propofol-induced changes in neurotrophic signaling in 14-day-old rat forebrain

“…Kod adulata, neurotrofini su važni posrednici neuronalne plastičnosti koji modulišu rast i remodelovanje aksona i dendrita, utiču na transport i recikliranje membranskih receptora, oslobađanje neurotransmitera, formiranje i pravilno funkcionisanje sinapsi (Lu i saradnici, 2005). Iako je pokazano da lokalna aplikacija neurotrofina indukuje lokalne promene u morfologiji neurona (Campenot, 1977;Poo, 2001), i dalje je nepoznato na kojoj razdaljini neurotrofini mogu ispoljavati svoje dejstvo.…”