Topic 4-Neurotransmitters Flashcards
Where do neurotransmitters act?
Neurotransmitters act at synapses in the synaptic cleft.
How do neurotransmitters affect target cells?
They have direct, rapid effects on specific target cells.
How quickly do the effects of neurotransmitters typically occur?
The effects of neurotransmitters usually occur quickly, within milliseconds to seconds, and are usually short-lived.
Where do neuromodulators act in relation to the synaptic cleft?
Neuromodulators act at a distance from the synaptic cleft.
How do neuromodulators influence cells?
They are released into the extracellular fluid, affecting many cells.
What is a notable characteristic of the effects of neuromodulators?
The effects of neuromodulators manifest slowly, over seconds, and typically last longer, ranging from minutes to days.
Criteria for classification as a NT: 3
1) Located in presynaptic region (usually in vesicles).
2) Released with activation or depolarization of the presynaptic terminal (Ca 2+ dependent).
3)Specific receptors must be present on the postsynaptic cell.
Two Types of NT
1)Small-molecule neurotransmitters (amino acids, acetylcholine, purines and biogenic amines)
2) Neuropeptides
Example of Excitatory NT:
1) Glutmate (main fasting acting NT in the CNS)
2) Aspartate
Example of Inhibitory NT
1) GABA (major inhibotry) 2) Glycine
Small molecule neurotransmitters can act as both
fast-acting neurotransmitters and neuromodulators.
Examples of small molecule NT
- Dopamine: Reward
Norepinephrine: Alertness
Epinephrine: Stress
Serotonin: Mood
Histamine: Wakefulness
Where is acetylcholine (ACh) primarily found in the nervous system?
ACh is a major conveyer of information in the peripheral nervous system (PNS).
What are the two main receptor subtypes for acetylcholine (ACh)?
ACh has two main receptor subtypes: nicotinic and muscarinic.
What is the role of acetylcholine (ACh) in the central nervous system (CNS)?
In the CNS, ACh is slower-acting and involved in neuromodulation, particularly in movement control and the selection of objects of attention.
How do nicotinic and muscarinic receptors differ in their action?
Nicotinic receptors are fast-acting, as seen at the neuromuscular junction, while muscarinic receptors are slower-acting, G-protein-coupled receptors. Muscarinic receptors are also found in the CNS.