Neurotransmitters Flashcards
Describe the overview of Neurotransmitters
- Chemicals used for neuronal communication with the body and the brain
- 50+ different neurotransmitters have been identified
- Classfied chemically and functionally (as excitatory or inhibitory or both [dependent upon receptor type])
- Excitatory (E) neurotransmitters cause depolarization
- Inhibitory (I) nurotransmitters cause hyperpolarization
- Both: Acetylcholoine is excitatory at skeletal muscle but inhibitory at cardiac muscle
Excitatory (E) neurotransmitters cause ____________?
depolarization
Inhibitory (I) neurotransmitters cause _________?
hyperpolarization
What are the chemical classifications of Neurotransmitters?
Acetylcholine
Biogenic amines
Amino acids
Peptides
Novel messengers (Purines, Gasses)
Describe Acetylcholine (CNS & PNS)
- First neurotransmitter identified, and best understood
- Released at the neuromuscular junction (nerve-muscle interface)
- Synthesized and enclosed in synaptic vesicles
- Degraded by the enzyme acetylcholinesterace (AChE)
- Released by:
- -All neurons that stimulate skeletal muscle (excitatory)
- -many neurons in the autonomic nervous system (E & I)
Describe Biogenic Amines (CNS & PNS)
- Broadly distributed in the brain and include:** Catecholamines & Indolamines**
- Play a key role in emotional behaviors and our sleep-wake cycles
Name the catecholamines
Dopamine (E or I)
Norepinephrine (E or I)
Epinephrine (E)
What is the function of Dopamine?
E or I
What is the function of Norepinephrine?
E or I
What is the function of Epinephrine?
E
Name the Indolamines
Serotonin (I)
Histamine (E or I)
What is the function of Serotonin?
I
What is the function of Histamine?
E or I
Name the Amino Acids (CNS only)
GABA (I) - key inhibitory neurotransmitter of Brain
Glutamate (E) - Learning & Memory; “Stroke Neurotransmitter”
Glycine (I) - key inhibitory neurotransmitter of spinal cord
What is the function of the Amino Acid GABA?
Key inhibitory Neurotransmitter of BRAIN
What is the function of the Amino Acid Glutamate?
(E)
Learning & Memory
“Stroke Neurotransmitter”
What is the function of the Amino Acid Glycine?
(I)
Key inhibitory Neurotransmitter of the SPINAL CORD
Describe the Peptide neurotransmitters (CNS & PNS)?
Includes:
- Beta endorphin, dynorphin, and enkephalins (I): natural opiates (inhibit pain)
- **Substance P (E) **- provokes pain sensation
- “gut brain peptides” - involved with appetite, anxiety, growth hormone release
Describe the Novel Messengers neurotransmitters (CNS & PNS)
ATP (E or I): provokes pain sensation
Nitric oxide (a.k.a. NO): (E or I): gas which causes vasodilation; involved in learning/memory
What is the function of Nitric oxide (NO)?
- (E or I)
- Novel messenger
- gas which causes vasodilation: involved in learning/memory
What is the function of Substance P?
- (E)
- Peptide (CNS and PNS)
- provokes pain sensation
What is the function of “Gut-Brain peptides”?
Peptide neurotransmitters involved with appetite, anxiety, growth hormone release
What is the function of ATP?
(E or I)
Novel messenger neurotransmitter (CNS or PNS)
provokes pain sensation
What are the two kinds of Neurotransmitter Receptor Mechanisms?
Direct: neurotransmitters that open channels
Indirect: neurotransmitters that act through second messengers
Describe Direct neurotransmitters
- Open ion channels
- promote rapid responses
- ex: ACh and amino acids
Describe Indirect neurotransmitters
- Act through second messengers
- promote long-lasting effects
- ex: biogenic amines, peptides, and dissolved gasses
