Lecture 12 Flashcards
What are the 4 requirements to identify neurotransmitters?
1) chemical must be synthesized in neurons/otherwise present in it
2) when neuron is active, chemical must be released and produce a response on some target
3) same response as step 2 is obtained when chemical is placed experimentally
4) mechanism must exist to shut it down
What are small-molecule transmitters? (1st class/four)
Quick acting transmitters, often synthesized from dietary nutrients (ex: acetylcholin, dopamine, serotonin, epinephrine, glutamate, GABA)
How is acetylcholine synthesized?
Choline creates acetyl coenzyme A (Acetyl CoA)
Acetate creates Choline acetyltransferase ChAT)
Acetyl CoA carries acetate to synthesis site, ChAT transfers acetate to choline, to form ACh
How is acetyl choline broken down?
Acetylcholinesterase is used to take back choline and acetate into presynaptic neuron to be reused-key for stopping signal. Detaches acetate from choline.
What kinds of things prevent acetylcholine reuptake?
Drugs for Alzheimers, Serrin Gas, pesticides.
What are peptide transmitters (2nd class/4)
Result from protein synthesis- opiods (pain management), corticosteroids (stress-related hormones), oxytocin (involved in childbirth etc)
What is an example of a lipid transmitter (3rd class/4)
Includes endocannabinoids.
What are the endocannabinoids?
Class of lipid transmitter that includes anandamide and 2-AG. Synthesized at the POST synaptic membrane. Not stored in vesicles, synthesized on demand, act as retrograde neurotransmitters, CB1 receptors found at glutamate and GABA synapses.
What are the transmitter gases (4th class/4)
Synthesized in the cell as required. Diffuses away from cell and activate metabolic processes. Modulates production of other neurotransmitters-activates/slows cellular metabolism.
What types of transmitter gasses activate vs slow cellular metabolism?
Nitric oxide and carbon monoxide activate, hydrogen sulfide slows.
What are the 2 widespread (small-molecule) neurotransmitters seen throughout the brain?
1) Glutamate (main excitatory neuron), involved in a form of neuroplasticity associated with memory.
2) GABA (main inhibitory neurotransmitter), regulates excitation.
What happens when things go wrong in the ion channels?
Channelopathies- juvenile myoclonic epilepsy- a type of seizure that includes hypnic jerks
Why does JME occur specifically?
Due to the GABA receptor being abnormal-less sensitive to GABA, less inhibition, which causes activation where there shouldn’t be.
What are the activating systems?
Neural pathways that coordinate brain activity through a single neurotransmitter. Cell bodies are located in the brain stem and the axons are distributed over a wide region.
What is the cholinergic system (activating system)
Active in maintaining attention, thought to also play a role in memory. Loss of these neurons is related to Alzheimer’s disease.
What is the Dopaminergic System (activating system).
Contains 2 major pathways: 1) Nigrostriatal-normal motor behaviour
2) Mesolimbic- reward pathway.
What is the Noradrenergic system (activating system)
Maintains emotional tone. Increases and decreases in NE are related to mania and depression.
What is the serotonergic system? (activating system)
Active in maintaining waking brain activity-decreases are related to depression.
What is Parkinsons Disease?
A progressive degenerative disorder-1st described in 1817. Causes a reduction of movement.
What are some of the positive symptoms of Parkinson’s disease?
Tremors at rest (pill rolling), muscular rigidity (increased tone), involuntary movements (constant, so the person is always tired).
What are the negative symptoms of Parkinson’s disease?
Disorder of posture, righting, locomotion. Speech disturbances, Akinesia (slow movement).
What was Parkinson’s disease first described as?
Shaking Palsy.
When is the mean onset and early onset of Parkinson’s?
Mean: 60
Early: 20-50
