Module 3 Flashcards
What are the four requirements resulting in resting potential?
- Capacitance: - 70 mV
- Potassium leak channels/Sodium leak channels
- Sodium-potassium exchange pump
- Negatively charged proteins
What is the outcome of an action potential?
- Resting State
- Depolarization - Na+ channels open; flows in
- Overshoot - Peak Na+ influx
- Repolarization - K+ channels open; flows out
- Hyperpolarization - Delayed closing of K+ channels
- Refractory period - short period after the neuron cannot fire
What are the types of subthreshold potentials that affect the production of action potential?
result from ligands (neurotransmitters or modulators) binding receptors resulting in either excitatory or inhibitory changes in the membrane potential.
What is the purpose of membrane potential?
helps to maintain cellular homeostasis, drive active transport, and manage cellular communication and coordination.
What is the purpose of an action potential?
It opens voltage gated calcium channels which allow the release neurotransmitters or neuromodulators which will bind receptors on other membranes (or on the same membrane) to continue or modify communication or action.
What is an excitatory potential?
are those changes resulting in depolarizing changes, inhibitory potentials are those that result in increases in the membrane potentials beyond rest (typically).
What are ligand-dependent receptors?
What are the ions that contribute to excitatory postsynaptic potential (EPSP)?
Na+ and Ca2+
What are the ions that contribute to inhibitory postsynaptic potential (IPSP)?
K+
Cl-
What is the purpose of EPSP?
Subthreshold potentials can summate… both
temporally and spatially.
fEPSPs bring the membrane potential closer
and closer to threshold, where voltage-gated
sodium channels (which are all or none) will
open and initiate action potential
Action potential is conducted to the terminal where
it creates the voltage change necessary to
cause the release of NTx…
What is the purpose of EPSP?
IPSPs make it harder for the membrane to
generate action potential by increasing the
difference in charge between the inside and
outside of the membrane… making the
membrane more stable.
This can reduce fatigue of a system, make muscle
contractions more controlled, and manage
balance in competing systems, among others.
What is the outcome of binding to NMDA receptor?
The channel is most sensitive to glutamate. Allows Na+, K+, and Ca2+ to flow through the channel
What is Neurotransmitter Inactivation? Example of this?
involves breakdown of the NTx molecule so it is unable to bind or remain bound
ACh and AChE which breaks ACh down into acetate ions and choline.
What is Endogenous?
“born within”
• Substance made by and secreted from within a cell
• Must be released from inside the body or cell
What is Exogenous?
“born outside”
• Substance made outside the body; or brought from the inside to the outside to be delivered from the outside.
What is an agonist?
Drugs that bind to physiological receptors and mimic the regulatory effects of the endogenous signaling compounds
Ligands that activate a receptor to produce a biological response
What is an antagonist?
Ligands that block agonist mediated response (rather than eliciting a biological response from binding itself)
What are potentiators?
Act to enhance the activity or effect of the agonist, without binding to the receptor of the agonist
What are some examples of potentiators?
• Substances that increase agonist release: like Black-Widow Spider venom.
• Substances that block reuptake of the agonist: like SSRIs
• Substances that inhibit chemical inactivation: like treatments for myasthenia gravis, or Sarin Gas (discussed later)
What are inhibitors? What are some examples?
act to lessen the activity or effect of the agonist, without binding to the receptor of the agonist.
• Substances that decrease agonist release: like botulinum toxin (BoTox)
• Substances that enhance chemical inactivation: AChE analogues
What are the cannabinoids as a treatment for Alzheimer’s Disease?
Neuroprotection
B-amyloid peptide aggregation inhibition
Inhibition of AChE activity
Anti-excitotoxicity
Anti-neurinflamatory
Antioxidant activity
What is membrane potential?
It is fundamental for cellular communication, energy production, and the overall proper functioning of cells, especially in excitable tissues like nerve and muscle cells.
What happens with myelinated axons?
LESS CAPACITANCE
What does reputable involve?
a receptor on the presynaptic cell that has high affinity for the NTx and essentially pulls it back into the presynaptic terminal, even before it binds, sometimes.
Is acetylcholine endogenous or exogenous? Or Both?
Endogenous
Is morphine endogenous or exogenous? Or Both?
Exogenous
What are most all antagonist endogenous or exogenous?
EXOgenous
What does AChE been shown to do when inhibited by essential oils?
Increasing the amounts of ACh in the brain, enhancing memory
What does BoTox inhibit the release of? What is BoTox a treatment for?
ACh, causing decreased muscle tone… as a treatment for spasticity, migraine headache and of course, wrinkles
What is Choline Acetyl Transferase (ChAT)?
is the synthetic enzyme used by the neuron (usually in the terminal) to synthesize ACh.
Why do muscle fatigue and tremor do not result from insufficient neurotransmitters?
The fact that choline is taken up and conserved, and that the transmitter is reformed in the terminal
What type of chemical inactivation for ACh?
Acetylcholinesterase (AChE)
