Pharmacology lecture 13

HideShow resource information
What do local anaesthetics prevent?
localised pain and also tactile sensation
1 of 20
What do general anaesthetics do?
Induce loss of consciousness
2 of 20
How do local anaesthetics work?
Block voltage gated Na+ channels so no action potential.
3 of 20
The effect of local anaesthetics
Interact with the alpha-subunit and physically 'plug' transmembrane pore. Binds in the ionised (hydrophilic) form. Binding area is located in the inner end of channel
4 of 20
What are the 3 subunits of voltage gated ion channels?
alpha, beta 1 and beta 2
5 of 20
the alpha-subunit =
a single polypeptide. Contains extracellular domains. 4 transmembrane domains each comprising of 6 alpha-helical regions
6 of 20
The beta1-subunit =
subunits flank alpha subunits - not linked
7 of 20
The beta2-subunit =
linked covalently to alpha
8 of 20
When voltage varies what happens in voltage gated ion channels?
voltage sensors change their orientation - this determines the configuration of the entire domain and controls opening/closing of a pore
9 of 20
Most anaesthetics are....
weak bases
10 of 20
What does the general structure of local anaesthetics consist of?
Aromatic group, ester or amide group and amine group
11 of 20
Local anaesthetics: what does the basic side chain ensure?
That the molecules are ionised at physiological pH
12 of 20
Local anaesthetics: What does the aromatic domain ensure?
Lipid solubility
13 of 20
Local anaesthetics: How is the action limited?
By the hydrolysis of ester/amide bond and by lipid solubility
14 of 20
Local anaesthetics: Where does ionisation take place?
Inside the axon
15 of 20
Local anaesthetics block conduction in ...... .......... fibres more effectively
small diameter
16 of 20
How do we restrict the site of action of local anaesthetics and prolong the action?
Coadminister with adrenaline
17 of 20
How do we accelerate the speed of onset of local anaesthetics?
Use slightly alkaline solution - assist n absorption into nerve tissue
18 of 20
What are the side effects of local anaesthetics? CNS, CV
CNS: confusion and agitation CV: Hypotension, inhibit sympathetic activity, inhibit sodium conductance
19 of 20
How does a use dependant block occur with local anaesthetics?
occurs because the anaesthetic gains access to and had higher affinity for channels more readily when it is open and/or inactive
20 of 20

Other cards in this set

Card 2

Front

What do general anaesthetics do?

Back

Induce loss of consciousness

Card 3

Front

How do local anaesthetics work?

Back

Preview of the front of card 3

Card 4

Front

The effect of local anaesthetics

Back

Preview of the front of card 4

Card 5

Front

What are the 3 subunits of voltage gated ion channels?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Local anaesthetics resources »