Neuropharmacology, General & Local Anesthetics, Opiods

What are local anesthetics?

Drugs that prevent or relieve pain by interrupting nerve conduction.

What is the mechanism of action of local anesthetics?

They block voltage-dependent Na+ channels, preventing nerve signal transmission.

What was the first local anesthetic discovered?

Cocaine.

What are the two main classifications of local anesthetics based on linkage type?

Amide-linked (e.g., lidocaine, bupivacaine) and ester-linked (e.g., procaine, tetracaine).

How does pH affect local anesthetic activity?

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.

What is the order of Na+ channel affinity for local anesthetics?

Inactive > Open > Resting.

How does the presence of a vasoconstrictor (e.g., epinephrine) affect local anesthetic duration?

It prolongs the effect by decreasing absorption.

What is neuropharmacology?

The study of how drugs affect neurons and the nervous system.

What is the difference between afferent and efferent nerves?

Afferent nerves carry sensory information to the CNS, while efferent nerves carry signals to the effector organs.

What are catecholamines, and give examples?

Water-soluble monoamines that act as neurotransmitters, including dopamine, epinephrine, and norepinephrine.

What is the difference between the sympathetic and parasympathetic nervous systems?

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.

What are the primary neurotransmitters and receptors in the sympathetic system?

Norepinephrine (NE) acts on alpha (𝛂) and beta (𝛃) adrenergic receptors.

What are the main types of cholinergic receptors?

Nicotinic (ion channels) and muscarinic (GPCRs).

What enzyme degrades acetylcholine at synapses?

Acetylcholinesterase (AChE).

What are opioid analgesics?

Drugs that inhibit pain response by acting on opioid receptors.

What are the three main sources of opioids?

Natural (morphine, codeine), semi-synthetic (heroin), and synthetic (fentanyl).

What are the four major opioid receptors?

Mu (µ), Delta (𝛅), Kappa (k), and Nociceptin/Orphanin FQ (NOP).

Which receptor is primarily responsible for opioid-induced analgesia?

The Mu (µ) receptor.

What is the main cause of death in opioid overdose?

Respiratory depression.

What is naloxone (Narcan) used for?

It is an opioid antagonist that reverses opioid overdose.

What common side effect do opioids have on the gastrointestinal system?

Severe constipation due to reduced peristalsis.

What are general anesthetics?

Drugs that produce reversible CNS depression, leading to loss of response to external stimuli.

What are the primary goals of a good general anesthetic?

Reversible sleep, analgesia, reflex suppression, muscle relaxation, amnesia, and minimal respiratory/cardiovascular suppression.

What are two main types of general anesthetics?

Injectable (IV) and inhalational.

Name an example of an inhalational anesthetic.

Isoflurane.

What is the main mechanism of action for most general anesthetics?

Positive modulation of GABA-A receptors, leading to increased inhibition in the CNS.

How do NMDA receptor blockers (e.g., ketamine) produce anesthesia?

By blocking excitatory neurotransmission mediated by glutamate.