Effects of argon laser irradiation on polar excitations in frog sciatic nerve.
OBJECTIVE
Since the mechanisms underlying the effects of low-power laser irradiation on the nervous system remain unclear, we examined whether such irradiation can influence ionic channels of the nerve membrane using the law of polar excitation in isolated frog sciatic nerve.


METHODS
Using 43 frogs (Xenopus laevis), nerve preparations were stimulated at 0.5/second using a 10-millisecond pulse at supramaximal intensity. Ar+ laser irradiation (457, 488, 514 nm; 50, 75, 100 mW) was applied for 30 minutes to the portion between the anode and cathode stimulating electrodes.


CONCLUSIONS
Ar+ laser irradiations (457, 488 nm; 50 mW) blocked the generation of anode-break-excitation, rather than cathode-make-excitation. Such a selective effect occurred when applying a blocker of hyperpolarization-activated cation current (Ih) channel, ZD7288. Ar+ laser irradiation may influence Na+ channels in addition to Ih channels.
Matsuda
Yoshiki
Y
Department of Bioengineering, Faculty of Engineering, Soka University, Hachioji, Tokyo, 192-8577, Japan. ymatsuda@t.soka.ac.jp
Niwa
Mayuka
M
Iwai
Hiromasa
H
Kogure
Shinichi
S
Honjoe
Nobuyuki
N
Komatsu
Mitsuaki
M
Ishii
Yoshio
Y
Watanabe
Kazuhiro
K
D000200:Action Potentials / Q000528:radiation effects*; D000818:Animals; D001128:Argon; D004558:Electric Stimulation; D004594:Electrophysiology; D007834:Lasers; D012584:Sciatic Nerve / Q000502:physiology* / Q000528:radiation effects*; D014982:Xenopus laevis
D001128:Argon