Louis F. Reichardt and Fariñas Isabel
- Published in print:
- 1998
- Published Online:
- May 2009
- ISBN:
- 9780195111668
- eISBN:
- 9780199865833
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195111668.003.0006
- Subject:
- Neuroscience, Molecular and Cellular Systems, Development
Neurotrophic factors are important regulators of the development and maintenance of vertebrate nervous system. During the development of the nervous system, neuronal populations undergo a process of ...
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Neurotrophic factors are important regulators of the development and maintenance of vertebrate nervous system. During the development of the nervous system, neuronal populations undergo a process of naturally occurring cell death at a time when their axons are innervating target areas. This mechanism ensures a balance between the size of an innervating population and the size of its target territory. Nerve growth factor (NGF) was the first neurotrophic factor to be discovered. More recent work has shown that other molecules are secreted by target organs that regulate neuronal survival and differentiation. This chapter focuses on neurotrophins with brief descriptions of the actions of these other molecules.Less
Neurotrophic factors are important regulators of the development and maintenance of vertebrate nervous system. During the development of the nervous system, neuronal populations undergo a process of naturally occurring cell death at a time when their axons are innervating target areas. This mechanism ensures a balance between the size of an innervating population and the size of its target territory. Nerve growth factor (NGF) was the first neurotrophic factor to be discovered. More recent work has shown that other molecules are secreted by target organs that regulate neuronal survival and differentiation. This chapter focuses on neurotrophins with brief descriptions of the actions of these other molecules.
Vanessa J. Auld
- Published in print:
- 1997
- Published Online:
- March 2012
- ISBN:
- 9781872748542
- eISBN:
- 9780191724367
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9781872748542.003.0013
- Subject:
- Neuroscience, Development
The glial cells of insects have been investigated since the days of Ramón y Cajal. Consequently there is a wealth of information about a range of insects and the different classes of their glia. This ...
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The glial cells of insects have been investigated since the days of Ramón y Cajal. Consequently there is a wealth of information about a range of insects and the different classes of their glia. This chapter focuses on discoveries made in the last few years, as the advent of new molecular markers specific for glia has led to dramatic advances in the characterization and analysis of glia in insects. The combination of these new markers with molecular genetics has provided an avenue to address the roles glia play in nervous system development. The chapter describes the functions of glia during development of the insect nervous system, with an emphasis on the many subtypes of nerve-tract-associated glia.Less
The glial cells of insects have been investigated since the days of Ramón y Cajal. Consequently there is a wealth of information about a range of insects and the different classes of their glia. This chapter focuses on discoveries made in the last few years, as the advent of new molecular markers specific for glia has led to dramatic advances in the characterization and analysis of glia in insects. The combination of these new markers with molecular genetics has provided an avenue to address the roles glia play in nervous system development. The chapter describes the functions of glia during development of the insect nervous system, with an emphasis on the many subtypes of nerve-tract-associated glia.
Patrick Beckers and Jörn von Döhren
- Published in print:
- 2015
- Published Online:
- March 2016
- ISBN:
- 9780199682201
- eISBN:
- 9780191813436
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199682201.003.0016
- Subject:
- Biology, Animal Biology
Nemertea is a spiralian phylum comprising approximately 1300 species of mostly marine, nocturnal predators. Prey is captured with an eversible proboscis housed in a dorsally located fluid filled ...
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Nemertea is a spiralian phylum comprising approximately 1300 species of mostly marine, nocturnal predators. Prey is captured with an eversible proboscis housed in a dorsally located fluid filled secondary body cavity, called rhynchocoel. Three major clades are recognized: Hoplonemertea, Pilidiophora, and Palaeonemertea. The main components of the nemertean nervous system are a ring-shaped brain around the rhynchocoel, and paired lateral, longitudinal medullary cords that are confluent with the ventral brain lobes. Additional, variable components of the nervous system are longitudinal cephalic, oesophageal, and proboscis nerves and various plexuses. Sensory organs comprise eyes, cerebral organs, frontal organs, and various epidermal sensory structures. Most of the canonic spiralian neurotransmitters have been detected, with FMRFamide-like neuropeptides being the most prevalent. Larvae of palaeo- and hoplonemertean species show virtually no transitory nervous elements, while the pilidium-larva of Pilidiophora possesses an extensive transitory larval nervous system. Among the first definite neural elements to develop in all species is the brain ring, followed by the lateral medullary cords. Data on neural development and morphology of other spiralian clades, as well as molecular data, support the scenario that a frontal brain with paired lateral medullary cords as present in Nemertea represents the ancestral spiralian nervous system architecture.Less
Nemertea is a spiralian phylum comprising approximately 1300 species of mostly marine, nocturnal predators. Prey is captured with an eversible proboscis housed in a dorsally located fluid filled secondary body cavity, called rhynchocoel. Three major clades are recognized: Hoplonemertea, Pilidiophora, and Palaeonemertea. The main components of the nemertean nervous system are a ring-shaped brain around the rhynchocoel, and paired lateral, longitudinal medullary cords that are confluent with the ventral brain lobes. Additional, variable components of the nervous system are longitudinal cephalic, oesophageal, and proboscis nerves and various plexuses. Sensory organs comprise eyes, cerebral organs, frontal organs, and various epidermal sensory structures. Most of the canonic spiralian neurotransmitters have been detected, with FMRFamide-like neuropeptides being the most prevalent. Larvae of palaeo- and hoplonemertean species show virtually no transitory nervous elements, while the pilidium-larva of Pilidiophora possesses an extensive transitory larval nervous system. Among the first definite neural elements to develop in all species is the brain ring, followed by the lateral medullary cords. Data on neural development and morphology of other spiralian clades, as well as molecular data, support the scenario that a frontal brain with paired lateral medullary cords as present in Nemertea represents the ancestral spiralian nervous system architecture.
