![]() |
|
|
1 Departments of Anesthesia and Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
The local anesthetic action of procaine or lidocaine on intact frog sciatic nerves is increased at an alkaline pH. In completely desheathed frog sciatic nerves it is possible to demonstrate a transient potentiation of lidocaine or procaine block upon decreasing the pH of the solution from 9.2 to 7.2. However, at equilibrium the block by procaine is always greater at pH 9.2 than 7.2; whereas, block by lidocaine is about the same at the two pH's. By contrast, in desheathed toad sciatic nerves, the block by lidocaine is greater, as is drug uptake, at an alkaline pH. Nerve block and lidocaine uptake in desheathed toad sciatic nerves at an alkaline pH can be increased by pre-equilibrating the nerves in neutral rather than alkaline anesthetic-free Ringer's solution. These observations at first appear paradoxical but can be reconciled with the proposal that block by the tertiary amine local anesthetics procaine and lidocaine is effected primarily by the cationic form; whereas. the free base form primarily determines penetration of the local anesthetic into tissue.
Submitted on August 4, 1969
This article has been cited by other articles:
![]() |
W. A. Visser, R. A. Lee, and M. J. M. Gielen Factors Affecting the Distribution of Neural Blockade by Local Anesthetics in Epidural Anesthesia and a Comparison of Lumbar Versus Thoracic Epidural Anesthesia Anesth. Analg., August 1, 2008; 107(2): 708 - 721. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Arakawa, Y. Aoyama, and Y. Ohe Block of the sacral segments in lumbar epidural anaesthesia Br. J. Anaesth., February 1, 2003; 90(2): 173 - 178. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Arakawa, Y. Aoyama, and Y. Ohe Epidural bolus injection with alkalinized lidocaine improves blockade of the first sacral segment - a brief report: [L'injection epidurale d'un bolus de lidocaine alcalinisee ameliore le blocage du premier segment sacre - un resume] Can J Anesth, June 1, 2002; 49(6): 566 - 570. [Abstract] [Full Text] [PDF] |
||||