Effect of pulsed Nd:YAG laser radiation on action potential conduction in isolated mammalian spinal nerves.
OBJECTIVE
Dental lasers are claimed to produce analgesia, but the mechanisms and extent of any effects are uncertain. This study investigated the effects of lasing on nerve conduction in isolated nerves.


METHODS
Pulsed Nd:YAG laser energy was applied to spinal nerves in vitro and effects were measured as attenuation of the compound action potential (CAP) evoked by electrical stimulation.


RESULTS
Lasing for 1 minute at 0.3-3.0 W caused a dose-dependent attenuation of all components of the CAP (P < 0.03). With 0.3-1.0 W power, the CAP recovered to > 95% of the control levels 7 minutes after lasing; recovery was incomplete after lasing at > 2.0 W.


CONCLUSIONS
Isolated nerves were remarkably tolerant of lasing. The degree of nerve conduction block increased with laser power. The data indicate that lasing could diminish sensations, including pain, mediated by peripheral nerves in soft tissues.
Orchardson
R
R
Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, United Kingdom. R.Orchardson@bio.gla.ac.uk
Peacock
J M
JM
Whitters
C J
CJ
D000200:Action Potentials / Q000528:radiation effects; D000818:Animals; D004307:Dose-Response Relationship, Radiation; D066298:In Vitro Techniques; D007834:Lasers; D009431:Neural Conduction / Q000528:radiation effects*; D051381:Rats; D013127:Spinal Nerves / Q000502:physiology / Q000528:radiation effects*