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Development of central catecholaminergic neuronal systems in the lizard Anolis sagrei

Rehn, Agneta LU (1998)
Abstract (Swedish)
Popular Abstract in Swedish

Catecholaminerna dopamin, noradrenalin och adrenalin är en grupp transmittorsubstanser som är involverade i olika funktioner i det centrala nervsystemet. De olika catecholaminerna bildas med hjälp av specifika enzymer. Tyrosin hydroxylas (TH) omvandlar L-DOPA till dopamin (DA), som i sin tur omvandlas av enzymet dopamin ß-hydroxylas (DBH) till noradrenalin, som till sist omvandlas till adrenalin av enzymet phenylethanolamin-N-methyltransferas (PNMT).



Jag har studerat de catecholaminerga cellgrupperna och fibersystemen i hjärnan hos den bruna anolisödlan Anolis sagrei, genom att kartlägga deras utbredning i den vuxna hjärnan samt undersöka när de olika cellgrupperna... (More)
Popular Abstract in Swedish

Catecholaminerna dopamin, noradrenalin och adrenalin är en grupp transmittorsubstanser som är involverade i olika funktioner i det centrala nervsystemet. De olika catecholaminerna bildas med hjälp av specifika enzymer. Tyrosin hydroxylas (TH) omvandlar L-DOPA till dopamin (DA), som i sin tur omvandlas av enzymet dopamin ß-hydroxylas (DBH) till noradrenalin, som till sist omvandlas till adrenalin av enzymet phenylethanolamin-N-methyltransferas (PNMT).



Jag har studerat de catecholaminerga cellgrupperna och fibersystemen i hjärnan hos den bruna anolisödlan Anolis sagrei, genom att kartlägga deras utbredning i den vuxna hjärnan samt undersöka när de olika cellgrupperna (dopaminerga, noradrenerga och adrenerga) uppträder i härnan och näthinnan under embryonalutvecklingen. Undersökningarna har utförts med immunohistochemiska metoder, varvid jag har använt antikroppar som är speciellt riktade mot transmittorsubstansen DA och mot enzymerna TH, DBH och PNMT.



Mina resultat visar att catecholaminer uppträder i hjärnan från det att embryot är 5 dagar gammalt (tidigt stadium 32). De första dopaminerga cellerna uppträder i diencephalon, i laterala hypothalamus (A11), och följs av dopaminerga celler i andra delar av diencephalon och mesencephalon. Därefter uppträder dopaminerga celler i telencephalon, rhombencephalon och ryggmärgen. De sista områdena uppträder precis innan kläckningen (stadium 40) och utgörs av dopaminerga celler i de olfaktoriska bulberna och L-DOPAerga celler längs aqueductus cerebri. Med några få undantag är de flesta immunoreaktiva områdena i hjärnan först TH immunoreaktiva för att senare också bli DA immunoreaktiva. Det noradrenerga området A6 visar tidigt (stadium 36) immunoreaktivitet mot TH och senare, strax innan kläckningen (stadium 39), också mot DA och DBH. Det adrenerga området A1/C1 visar också TH immunoreaktivitet tidigt (stadium 36), vid nästa stadium DA immunoreaktivitet, och slutligen vid stadium 39 också PNMT immunoreaktivitet. Immunoreaktiva fibrer finns i alla områden där det finns immunoreaktiva cellgrupper och från stadie 36/37 framträder dopaminerga fibrer i stora delar av hjärnan. PNMT immunoreaktiva fibrer kunde bara påvisas i A1/C1 området under embryonalutvecklingen, medan inga DBH immunoreaktiva fibrer observerades före kläckningen. Däremot uppträder både DBH och PNMT immunoreaktiva fibrer i olika delar av hjärnan hos juvenila och vuxna anolisödlor. Catecholaminernas utbredning i hjärnan hos Anolis sagrei följer i stort det grundläggande mönster som tidigare påvisats hos fiskar, grodor, reptiler och fåglar. Utvecklingssekvensen hos Anolis sagrei följer också ett för ryggradsdjur grundläggande mönster, men skillnader kan urskiljas framför allt mellan fisk/grod-gruppen och reptil/fågel-gruppen, dvs mellan anamnioter och amnioter.



I näthinnan (retina) hos Anolis sagrei observerades tre olika typer av dopaminerga amacrina celler. Vid sent stadium 34 framträder två olika typer av amacrina celler i det inre granulära skiktet, med fibrer i det inre plexiforma skiktet. Vid stadium 36 framträder ytterligare en typ av celler i det inre granulära skiktet med fibrer både i det inre granulära och i det inre plexiforma skiktet. Dessa celler representerar sannolikt interplexiforma celler. Under hela fosterutvecklingen ökar dessa tre celltyper i antal, med starkare immunoreaktivitet och tätare nätverk av fibrer i det inre plexiforma skiktet. De dopaminerga cellerna hos juvenila ödlor ser ut som i stadie 39-40. Både amacrinceller och interplexiforma celler har beskrivits i näthinnan hos andra vuxna ödlor, men deras utveckling har inte studerats tidigare. (Less)
Abstract
Catecholamines, comprising the neurotransmitters dopamine (DA), noradrenaline (NA) and adrenaline (A) are synthesized by specific enzymes (tyrosine hydroxylase (TH), dopamine ß-hydroxylase (DBH), phenylethanolamine-N-methyltransferase (PNMT)) in the central nervous system. The development and distribution of different catecholaminergic systems have been described in both the brain and retina of the lizard Anolis sagrei. The first dopaminergic neurons appear at early developmental stage 32 in the diencephalon, in the future lateral hypothalamic area (A11), followed by dopaminergic neurons in other areas of the diencephalon and in the mesencephalon. Then, dopaminergic neurons appear in the telencephalon, rhombencephalon and in the spinal... (More)
Catecholamines, comprising the neurotransmitters dopamine (DA), noradrenaline (NA) and adrenaline (A) are synthesized by specific enzymes (tyrosine hydroxylase (TH), dopamine ß-hydroxylase (DBH), phenylethanolamine-N-methyltransferase (PNMT)) in the central nervous system. The development and distribution of different catecholaminergic systems have been described in both the brain and retina of the lizard Anolis sagrei. The first dopaminergic neurons appear at early developmental stage 32 in the diencephalon, in the future lateral hypothalamic area (A11), followed by dopaminergic neurons in other areas of the diencephalon and in the mesencephalon. Then, dopaminergic neurons appear in the telencephalon, rhombencephalon and in the spinal cord. The last area appear just before hatching in the olfactory bulbs (dopaminergic) and in the area lining the cerebral aqueduct (L-DOPAergic). All areas with some exceptions are first immunoreactive (ir) to TH and at later stages also DA immunoreactive. The presumed noradrenergic area A6 and adrenergic area A1/C1 are both first THir and at later stages also DAir and DBHir (A6) or PNMTir (A1/C1). Dopaminergic fibers are observed in the area with dopaminergic neurons and from stage 36/37 also present in many other brain areas. PNMTir fibers appear only in the A1/C1 area during the embryonic stages, whereas DBHir fibers could not be observed during any of the embryonic stages. In juveniles and adults, no additional groups of dopaminergic neurons or fibers appear, whereas both DBHir and PNMTir are found scattered throughout the brain. The distribution of the major catecholamines have been identified in the brain of all nonmammals studied so far, including Anolis sagrei and a ?basic? temporal sequence of appearance during the embryonic development can be observed in the brain of nonmammals.



In the retina of Anolis sagrei, three types of dopaminergic amacrine cells are observed. Type 1 and 2 cells appear at late embryonic stage 34. At stage 36, a third type of dopaminergic cells appear in the retina, probably representing interplexiform cells. Both amacrine cells and interplexiform cells have been described in the retina of adult lizards, but the development of these cells have not previously been described. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof Ebbesson, Sven O. E., University of Alaska Fairbanks, Alaska, USA Alaska
organization
publishing date
type
Thesis
publication status
published
subject
keywords
double labelling, immunohistochemistry, interplexiform cells, amacrine cells, catecholamines, development, retina, Reptiles, brain, Zoology, Zoologi
pages
111 pages
publisher
Department of Zoology, Lund University
defense location
Högtidsalen, Lund
defense date
1998-10-16 10:00
external identifiers
  • Other:ISRN: LUNBDS/NBZS--98/1030--SE
language
English
LU publication?
yes
id
f20549a5-d02d-4356-ba13-fbb628fa8288 (old id 38934)
date added to LUP
2007-07-31 15:59:18
date last changed
2016-09-19 08:45:05
@misc{f20549a5-d02d-4356-ba13-fbb628fa8288,
  abstract     = {Catecholamines, comprising the neurotransmitters dopamine (DA), noradrenaline (NA) and adrenaline (A) are synthesized by specific enzymes (tyrosine hydroxylase (TH), dopamine ß-hydroxylase (DBH), phenylethanolamine-N-methyltransferase (PNMT)) in the central nervous system. The development and distribution of different catecholaminergic systems have been described in both the brain and retina of the lizard Anolis sagrei. The first dopaminergic neurons appear at early developmental stage 32 in the diencephalon, in the future lateral hypothalamic area (A11), followed by dopaminergic neurons in other areas of the diencephalon and in the mesencephalon. Then, dopaminergic neurons appear in the telencephalon, rhombencephalon and in the spinal cord. The last area appear just before hatching in the olfactory bulbs (dopaminergic) and in the area lining the cerebral aqueduct (L-DOPAergic). All areas with some exceptions are first immunoreactive (ir) to TH and at later stages also DA immunoreactive. The presumed noradrenergic area A6 and adrenergic area A1/C1 are both first THir and at later stages also DAir and DBHir (A6) or PNMTir (A1/C1). Dopaminergic fibers are observed in the area with dopaminergic neurons and from stage 36/37 also present in many other brain areas. PNMTir fibers appear only in the A1/C1 area during the embryonic stages, whereas DBHir fibers could not be observed during any of the embryonic stages. In juveniles and adults, no additional groups of dopaminergic neurons or fibers appear, whereas both DBHir and PNMTir are found scattered throughout the brain. The distribution of the major catecholamines have been identified in the brain of all nonmammals studied so far, including Anolis sagrei and a ?basic? temporal sequence of appearance during the embryonic development can be observed in the brain of nonmammals.<br/><br>
<br/><br>
In the retina of Anolis sagrei, three types of dopaminergic amacrine cells are observed. Type 1 and 2 cells appear at late embryonic stage 34. At stage 36, a third type of dopaminergic cells appear in the retina, probably representing interplexiform cells. Both amacrine cells and interplexiform cells have been described in the retina of adult lizards, but the development of these cells have not previously been described.},
  author       = {Rehn, Agneta},
  keyword      = {double labelling,immunohistochemistry,interplexiform cells,amacrine cells,catecholamines,development,retina,Reptiles,brain,Zoology,Zoologi},
  language     = {eng},
  pages        = {111},
  publisher    = {ARRAY(0x8ca5fa8)},
  title        = {Development of central catecholaminergic neuronal systems in the lizard Anolis sagrei},
  year         = {1998},
}