Study Guide Flashcards
(110 cards)
7 What is the role of the primary motor cortex?
The motor cortex controls body movements. It sends an axon down to the spinal cord to control motor efferent nerves.
38 Describe the removal of glutamate?
Glutamate is terminated by reuptake, primarily by astrocytes and covert glutamate back to glutamine by the enzyme glutamine synthetase. It is then transported back into the neuron.
38 Describe the synthesis of glutamate?
Glutamine is converted into glutamate by glutaminase. It occurs in the presynaptic terminal. High levels of glutamate in extracellular fluid are dangerous, producing excessive neuronal excitation and even cell death.
39 What are the types of glutamate receptors?
Glutamate is released to excite ( stimulus) other neurons. It is the main excitatory neurotransmitter in the central nervous system (EPSPs.)
Enhances activation of NMDA receptors overexcites cells and causes cell death ( by Way of Ca2+ influx. Which is known as excitotoxicity.
- GIve drugs that mimic glutamate and bind to NMDA receptors and cell loss follows.
- Implicated in Alzheimer’s Disease
39 What are the different types of glutamate receptors?
Glutamate binds to both inotropic & metabotropic receptors. Inotropic: NMDA, AMPA, Kainate. Metabotropic: mGluR1 - mGluR8 receptors.
NMDA, AMPA, and Kainate allow the passage of sodium ( Na+) and as a result depolarization occurs when glutamate binds to these receptors.
NMDA also allows the passage of Calcium ( Ca++) which activates second messengers within the cell.
N/A What is glutamate?
An essential amino acid that is used in the synthesis of proteins ( complicates localizing it). It is found in 80% of Neurons in the cortex.
41 AWhat are the functions of glutamate?
Learning and memory is also dependent on glutamatergic activity at the NMDA receptor.
- Block the NMDA receptor and animals do not perform well on a test of memory.
- Morris Walter Maze
41 What are the main functions of glutamate in the central nervous system?
Glutamate is released to excite (stimulate) other
neurons – main excitatory neurotransmitter in the
central nervous system (EPSPs). Learning & memory
42 What is the synthesis of GAMMA- AMINOBUTRIC ACID? ( GABA)
Glutamate is converted into GABA by glutamatic acid decarboxylase ( GAD)
42 Describe the removal of Gamma-aminobutric acid ( GABA?)
GABA is terminated by reuptake by Neurons & Astrocytes, which take up the GABA and convert it eventually back to glutamate by GABA Aminotransferase ( GABA-T.)
Glutamate is then converted to glutamine and transported back to the neuron.
43 What are the two main types of GABA receptors?
GABA binds to two main receptors: GABA (a) ionotropic & GABA (b) metabotropic
43 What are the mechanisms of action for the two main types of GABA receptors? GABA ( a) ionotropic & GABA ( b) metabotropic?
GABA ( a) allows the passage of Chloride ( Cl-) and as a result hyperpolarization occurs when GABA binds to this receptor.
There are multiple binding sites on the GABA(a) receptor ( Not just the one for GABA.)
44 What are the main functions of GABA in the central nervous system?
GABA is found high in concentrations in the brain and spinal cord, but is absent in the peripheral nervous system.
GABA is not an essential amino acid and is not used for the synthesis of proteins.
44 What are the main functions of GABA in the central nervous system?
GABA is released to suppress/inhibit the activity of other neurons,
It is the main inhibitory neurotransmitter in the central nervous system ( IPSPs.)
Lack of GABA = epileptic seizures ( convulsions)
Enhancing GABA activity reduces, anxiety, induced sleep, and reduces convulsions.
45 How do benzodiazepine drugs affect GABAergic neurotransmitters?
When benzodiazepine drugs ( BDZ) bind to the GABA(A) receptor, it potentiates the effect of GABA.
Such as creating anxiolytic effects ( reducing anxiety.)
46What is the role of dopamine in Parkinson’s disease and schizophrenia?
Cells that produce dopamine die in Parkinson’s patients. Give L-DOPA ( converted to dopamine) to treat symptoms.
Parkinson’s = shakiness ( tremors), stiffness, and slowed down movements.
Schizophrenia= thought to be result of too much dopamine ( blocks Dopamine D2 receptors.)
37 What is the mechanism of action of botulinum toxin ( Botox)?
Decreasing acetylcholine at the neurotransmitter junction will cause paralysis.
It blocks the release of acetylcholine
Causes a paralysis of that muscle due to a blockade of acetylcholine release from the incoming motor nerve fibers.
32 What are the two main types of acetylcholine receptors,and how do they differ in mechanisms of action?
Nicotinic ( ionotropic)
Nicotinic receptors allow the passage of sodium ( Na+)
Binding of nicotine receptors by acetylcholine causes depolarization.
Muscarinic ( metabotropic)
Are associated with stimulatory g-proteins
Leads to a series of intracellular signals.
Intracellular Signaling Mechanisms of Muscarinic Receptors
Figure for reference
33How can the same neurotransmitter have different effects on different target cells?
The same receptor can be associated with different functions. This is why location is important. The same neurotransmitter can have oppositive effects because of the different type of receptors. Hyperpolarization or depolarization??
31Describe the synthesis & removal of acetylcholine
Synthesis occurs in presynaptic terminal from choline ( organic compound), from fat in our diet.
Acetyl CoA and Choline are converted to Acetylcholine by the enzyme Choline Acetyltransferase ( ChAT).
Choline is the rate limiting step- determines the overall rate of synthesis
Removal
Acetylcholine is terminated by acetylcholinesterase ( AChE) in the synaptic cleft which converts acetylcholine into choline and acetate ( both of which are transported back into the cell)
34 What are the main functions of acetylcholine in the nervous system?
At the neuromuscular junction acetylcholine causes muscle contractions.
Associated with increased activity of the parasympathetic nervous system.
It is involved in learning & memory: scopolamine impairs acquisition of new information.
Sleep & wakefulness.
35 How is acetylcholine related to Alzheimer’s disease?
Donepezil ( Aricept) is used for Alzheimer’s Disease and it works by inhibiting acetylcholinesterase ( AChE) - treats the symptoms and not the disease