COGNITIVE SCIENCE 17 The Chemical Brain Part 1
description
Transcript of COGNITIVE SCIENCE 17 The Chemical Brain Part 1
![Page 1: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/1.jpg)
COGNITIVE SCIENCE 17
The Chemical Brain
Part 1
Jaime A. Pineda, Ph.D.
![Page 2: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/2.jpg)
Neurotransmitters I
![Page 3: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/3.jpg)
The Life Cycle of a Conventional NT
• Biosynthesis & Storage
• Release
• Receptor Action
• Inactivation
![Page 4: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/4.jpg)
Biosynthesis
Precursor(s) Transmitter
Enzyme(s)
![Page 5: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/5.jpg)
Storage
• Synaptic vesicles made by Golgi apparatus in cell body
• Precursors, enzymes, and vesicles are transported from cell body down axon to terminal
• At terminal, NTs are synthesized and packaged into vesicles
• Filled vesicles dock onto proteins in terminal
![Page 6: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/6.jpg)
Release
• Action potential opens channels for Ca++ to enter terminal membrane
• Vesicles to undock and move to membrane
• Vesicles fuse with membrane and empty transmitter into synapse (exocytosis)
![Page 7: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/7.jpg)
![Page 8: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/8.jpg)
![Page 9: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/9.jpg)
Receptor Action
• Ionotropic– Opens ion channel in receptor itself– Ions produce either excitation or inhibition– Fast action
• Metabotropic– Sets off cascade of chemical events– Can lead to ion channel opening on another protein– Can lead to other, long-term changes– Slower action
![Page 10: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/10.jpg)
![Page 11: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/11.jpg)
![Page 12: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/12.jpg)
Inactivation
Breakdown Products
Transmitter
Enzy
me(
s)
• Destruction • Reuptake
![Page 13: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/13.jpg)
![Page 14: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/14.jpg)
More on Receptors
• Gating– Ligand (activated by NT or drug)– Voltage (activated by depolarization)
• Location– Postsynaptic– Presynaptic
• Autoreceptor• Heteroreceptor
![Page 15: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/15.jpg)
PresynapticAutoreceptor=
![Page 16: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/16.jpg)
PresynapticHeteroreceptors
![Page 17: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/17.jpg)
Some Receptor and Other Changes
• Receptor number (up/down-regulation)
• Receptor affinity (low/high)
• Reuptake transporter number/affinity
• Enzyme levels
• Transmitter synthesis
• Axon growth
• Dendrite growth
• Etcetera
![Page 18: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/18.jpg)
![Page 19: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/19.jpg)
Hierarchy of NTs of Interest
Amino AcidsGlutamate (Glu)GABA
Biogenic AminesQuaternary Amines
Acetylcholine (Ach)Monoamines
CatecholaminesDopamine (DA)Norepinephrine (NE)
IndolaminesSerotonin (5-HT)
NeuropeptidesOpioid Peptides
EnkephalinsEndorphinsDynorphins
(Others: lipids, nucleosides, soluble gases)
![Page 20: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/20.jpg)
Amino Acid NTs
• High concentration in brain (micromolar)• Small vesicles• Point-to-point communication• Mostly cortex-to-cortex• Sensory-motor functions• Consistently excitatory or inhibitory• Mainly ionotropic receptors• Fast acting, short duration (1-5 ms)• Examples: Glutamate, Aspartate, GABA, Glycine
![Page 21: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/21.jpg)
Biogenic Amines
• Medium concentration in brain (nanomolar)• Small vesicles• Single-source divergent projections• Mainly midbrain to cortex• Modulatory functions• Excitatory or inhibitory by receptor• More metabotropic receptors than ionotropic, but plenty of
both• Slow acting, long duration (10-1000 ms)• Examples: Acetylcholine, Epinephrine, Norepinephrine,
Dopamine, Serotonin
![Page 22: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/22.jpg)
Neuropeptides
• Low concentration in brain (picomolar)• Large vesicles• Packaged in vesicles before transport to terminal• Co-localized with other transmitters• Interneuronal• Modulatory functions• Mostly inhibitory• Virtually all metabotropic• Slow acting, long duration (10-1000 ms)• Examples: Enkephalins, Endorphins, Oxytocin,
Vasopressin
![Page 23: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/23.jpg)
Modulatory Functions
• State-dependent effects
• Regulate influence of extrinsic vs. intrinsic activity
• Synchronization of areas/functions
• Motivational/emotional recruitment of mental resources
![Page 24: COGNITIVE SCIENCE 17 The Chemical Brain Part 1](https://reader031.fdocuments.net/reader031/viewer/2022020308/56815f82550346895dce8866/html5/thumbnails/24.jpg)