Neuropharmacology, General & Local Anesthetics, Opiods

Local Anesthetics

What are local anesthetics?
A: Drugs that prevent or relieve pain by interrupting nerve conduction.

Q: What is the mechanism of action of local anesthetics?
A: They block voltage-dependent Na+ channels, preventing nerve signal transmission.

Q: What was the first local anesthetic discovered?
A: Cocaine.

Q: What are the two main classifications of local anesthetics based on linkage type?
A: Amide-linked (e.g., lidocaine, bupivacaine) and ester-linked (e.g., procaine, tetracaine).

Q: How does pH affect local anesthetic activity?
A: LAs are weak bases; they must be uncharged to cross membranes but bind in their charged state. Infected tissue (lower pH) can reduce their effectiveness.

Q: What is the order of Na+ channel affinity for local anesthetics?
A: Inactive > Open > Resting.

Q: How does the presence of a vasoconstrictor (e.g., epinephrine) affect local anesthetic duration?
A: It prolongs the effect by decreasing absorption.

Neuropharmacology

Q: What is neuropharmacology?
A: The study of how drugs affect neurons and the nervous system.

Q: What is the difference between afferent and efferent nerves?
A: Afferent nerves carry sensory information to the CNS, while efferent nerves carry signals to the effector organs.

Q: What are catecholamines, and give examples?
A: Water-soluble monoamines that act as neurotransmitters, including dopamine, epinephrine, and norepinephrine.

Q: What is the difference between the sympathetic and parasympathetic nervous systems?
A: The sympathetic system ("fight or flight") increases heart rate and dilates pupils, while the parasympathetic system ("rest and digest") decreases heart rate and promotes digestion.

Q: What are the primary neurotransmitters and receptors in the sympathetic system?
A: Norepinephrine (NE) acts on alpha (𝛂) and beta (𝛃) adrenergic receptors.

Q: What are the main types of cholinergic receptors?
A: Nicotinic (ion channels) and muscarinic (GPCRs).

Q: What enzyme degrades acetylcholine at synapses?
A: Acetylcholinesterase (AChE).

Opioid Analgesics

Q: What are opioid analgesics?
A: Drugs that inhibit pain response by acting on opioid receptors.

Q: What are the three main sources of opioids?
A: Natural (morphine, codeine), semi-synthetic (heroin), and synthetic (fentanyl).

Q: What are the four major opioid receptors?
A: Mu (µ), Delta (𝛅), Kappa (k), and Nociceptin/Orphanin FQ (NOP).

Q: Which receptor is primarily responsible for opioid-induced analgesia?
A: The Mu (µ) receptor.

Q: What is the main cause of death in opioid overdose?
A: Respiratory depression.

Q: What is naloxone (Narcan) used for?
A: It is an opioid antagonist that reverses opioid overdose.

Q: What common side effect do opioids have on the gastrointestinal system?
A: Severe constipation due to reduced peristalsis.

General Anesthetics

Q: What are general anesthetics?
A: Drugs that produce reversible CNS depression, leading to loss of response to external stimuli.

Q: What are the primary goals of a good general anesthetic?
A: Reversible sleep, analgesia, reflex suppression, muscle relaxation, amnesia, and minimal respiratory/cardiovascular suppression.

Q: What are two main types of general anesthetics?
A: Injectable (IV) and inhalational.

Q: Name an example of an inhalational anesthetic.
A: Isoflurane.

Q: What is the main mechanism of action for most general anesthetics?
A: Positive modulation of GABA-A receptors, leading to increased inhibition in the CNS.

Q: How do NMDA receptor blockers (e.g., ketamine) produce anesthesia?
A: By blocking excitatory neurotransmission mediated by glutamate.

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