PHARMACOLOGY

Question 1

Describe the mode of action of Local anaesthetics

Answer 1

The LA is only active in the charged +ve form, it crosses them membrane of the cell in the uncharged form Once in the cytosol it can accept a proton. IN the charged state is capable of blocking Na channels

Question 2

How does the sensitivity to LAs change with axon diameter?

Answer 2

Sensitivity increases with a decreases axon diameter. The most sensitive axons are Type C (nociceptive) and type B fibres