Lecture 7 Flashcards
Where are nocicpetor cell bodies located?
Dorsal root ganglia near the spinal cord
What are specific inhibitors of pain pathways?
Analgesics
What are non-specific inhibitors of peripheral sensory. Include pain, motor and autonomic pathways.
Anesthetics
What inhibit conduction of action potentialsin all afferent and efferent nerve fibers?
Local anesthetics
Are local anesthetics hydrophobic or hydrophillic?
Hydrophobic
Local anesthetics are _____ bases either ester or amide linked
Weak
What do local anesthetics bind to in the blood?
Alpha-1-acid glycoprotein and albumin
If a local anesthetic is less hydrophobic will it have a greater or lesser plasma concentration.
Great plasma concentration (small Volume distribution)
Where will local anesthetics systemically travel to/
Capillary beds of the lungs
What are three ester linked local anesthetics?
Procaine, tetracaine, cocaine
How are ester linked local anesthetics metabolized?
By tissue and plasma esterases (pseudocholinesterases)
How are ester linked local anesthetics eliminated?
Via the kidney
What are 4 amide linked local anesthetics?
Lidocaine
Prilocaine
bupivicaine
articaine
How are amide linked local anesthetics metabolized?
P450 in the liver, some in the lungs
How are amide linked local anesthetics eliminated?
the kidney
How do local anesthetics work?
By individual Na channels in neuronal membranes
When do local anesthetics work best?
When you are in pain this means sodium channels will be open
What occurs when the time between action potentials is long compared to the time for dissociation of the local anesthetic from the Na channel
Tonic inhibition
What happens when there isn’t enough time b/w action potential and AP conduction increasingly inhibited at higher frequency of impulses?
Phase inhibition
Do local anesthetics interact w/ other channels?
yes they can (ex- K, Ca, ligand gated, several G-protein receptors) but usually no significant unless dealing with toxicities
This is primarily used for infiltration anesthesia and dental procedures. Rapidly metabolized by cholinesterases. Short-acting, low hydrophoicity- low potency
Procaine
Name the local anesthetic: long acting, highly potent due to high hydrophobicity. Metabolized by cholinesterases in plasma. Used for spinal and topical anesthesia.
Tetracaine
Name the local anesthetic: Only naturally occuring ester based local anesthetic. Inhibits catecholamien uptake peripherally and centrally = vasoconstriction and euphoria. Used in ophthalmic and topical anesthesia.
Cocaine
What are the 2 most commonly used local anesthetics, amide based?
Lidocaine
Prilocaine
