Lab 3: Neurotransmitters Flashcards
Most, if not all, cognitive processes are under control of what four modulating neurotransmitters?
dopamine,
noradrenaline,
serotonine and
acetylcholine
In what way is acetylcholine different from the other neurotransmitters?
Acetylcholine is not so much a modulator of ongoing neuronal activity as it is capable to activate neurons on its own. This is different from dopamine, serotonine and noradrenaline actions, that upgrade or weaken ongoing transmission, dependent on the type of receptor present.
For this reason of modulating ongoing neuronal activity what name is often given to the other neurotransmitters? (dopamine, serotonine and noradrenaline)
the latter transmitters are sometime called ‘neuromodulators’ instead of neurotransmitters.
What is used to stain Acetylcholine?
Choline Acetyltransferase (CHAT)
Name three synthesis areas of Acetylcholine
Medial septum
Vertical Limb of the diagonal band of Broca
Horizontal limb of the diagonal band of Broca
Where does the medial septum project to and what role does it therefore play?
Hippocampus; learning and memory
Where does the Vertical Limb of the diagonal band of Broca project to?
Cortical and subcortical areas such as the nucleus accumbens
What areas of interneurons are known of Acetylcholine? (3)
Accumbens cholinergic interneurons (In nucleus accumbens)
Neostriatal cholinergic interneurons (In caudate of the Putamen)
Cortical Cholinergic interneurons
Where do the fibers surrounding these interneurons come from?
It is unclear whether they come from the interneurons or the synthesis areas
How do the different layers of the cortex correlate to the Cortical Cholinergic interneurons?
In layer one there are a lot of cholinergic fibers
Interneurons are mostly located in layer 2 and 3
Describe dopamine
Dopamine is a real modulator of ongoing neuronal transmission and enhances or attenuates activity dependent on the type of dopamine receptor is available in the post synaps.
How is dopamine stained?
The slices are stained with tyrosine hydroxylase
What is also significant about tyrosine hydroxylase?
It is the enzyme important in the transfer from tyrosine to dihydroxy- phenylalanine (DOPA). From DOPA dopamine is synthesized.
How is dopamine transformed into noradrenaline? Why is this significant
dopamine is transformed to noradrenaline in noradrenergic neurons using the enzyme dopamine beta-hydroxylase. A tyrosine hydroxylase staining is therefore not specific for dopamine but also stains noradrenerge neurons and fibers.
Name two broad synthesis areas of Dopamine
=>Substantia Nigra
=>Ventral Tegmental Area (VTA) (A10)
What two areas included under substantia nigra?
Substantia Nigra pas compacta (A9)
Substantia Nigra pars reticular
Why can they conclude that this is dopamine?
It is observed in SN and VTA but immediately outside it,
Where else can dopamine synthesisers be found?
A8, A11-A17
Name projection areas of dopamine (no cells)
Caudatus putamen
Nucleus Accumbens
Which parts of the nucleus accumbens is correlated to which
Shell area- dense with dopaminergic fibres
Core- slightly less but still quite dense
Where are the receiving ends of the dopamine pathways located?
Caudatus Putamen
Singulate area of the prefrontal cortex
Posterior part of the hippocampus
How to the layers of the singulate area of the prefrontal cortex differ in terms of dopaminergic projections?
All layers are pretty dense but layer 2 and 5 are the densest for fibers (output layers)
How can it be assumed that these tracts are dopamine?
Because they branch off from the substantia nigra
How can parkinsons be detected early and how is that related to this topic
Before any motor skills are lost (due to lost dopamine cells in the SN), there is a loss of smell, caused by a loss of dopamine cells in the Tuberculum ofactorium (A16) of the olfactory bulbs. Here, there dopamine is also synthesised.
Are there dopamine neurotransmitters in the cerebellum?
Research indicated there is, but it is unsure whether they are dopamine or noradrenaline as they cannot be traced back.
What is the stain used to detect noradrenaline? Is this specific to noradrenaline?
The slices are stained with dopamine beta-hydroxylase (DBH), the enzyme important in the transfer from dopamine to noradrenaline. Therefor the DBH staining is specific for noradrenergic neurons and fibers.
Where is noradrenaline produced?
Locus coeruleus
How is serotonin stained? (2)
The slices are stained with 5-hydroxytryptamine (5-HT), or serotonin.
How is this unlike TH and DBH stainings?
here you stain the end product, serotonin itself.
Where is serotonin produced? (4)
Raphre Interpositus nucleus (Dorsal raphe dorsal, Dorsal raphe ventral, Medial raphe)
Raphe Magnus/ Pallidus nucleus
B9 serotonin cells and throughout the brainstem
Where can ‘star shaped’ serotonin cells be found and why is this?
in the dorsal raphe because they are polarised and have dendrites coming out of them
