Effects of low-power laser irradiation on the threshold of electrically induced paroxysmal discharge in rabbit hippocampus CA1.
In acute experiments using adult rabbits, we measured the paroxysmal discharge threshold (PADT) elicited by stimulation to the apical dendritic layer of the hippocampal CA1 region before and after low-power laser irradiation. Nd:YVO(4) laser irradiation (wavelength: 532 nm) was introduced into the same region as the stimulation site. The average PADT was 247 +/- 13 microA (n = 18) before laser irradiation, while after 5-min laser irradiation with 50, 75, and 100 mW, PADT was 333 +/- 40 (n = 4), 353 +/- 33 (n = 4) and 367 +/- 27 microA (n = 6), respectively. The latter two increments were statistically significant compared to the control (p < 0.05 and p < 0.01). After 10-min laser irradiation with 75 and 100 mW, PADT was 340 +/- 47 (n = 9) and 480 +/- 60 microA (n = 11; p < 0.01), respectively. Laser irradiation with a specific wavelength and average power offers the potential to suppress the generation of paroxysmal discharges in rabbit hippocampus CA1. Correlation analyses suggest that PADT increments are based on photochemical as well as photothermal effects of laser irradiation.
Kogure
Shinichi
S
Department of Bioinformatics, Faculty of Engineering, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, Japan. kogure@t.soka.ac.jp
Takahashi
Satoshi
S
Saito
Nobuaki
N
Kozuka
Kazuya
K
Matsuda
Yoshiki
Y
D000200:Action Potentials / Q000528:radiation effects; D000818:Animals; D001831:Body Temperature; D056547:CA1 Region, Hippocampal / Q000033:anatomy & histology / Q000502:physiology* / Q000528:radiation effects*; D004558:Electric Stimulation; D055724:Electrophysiological Phenomena; D004827:Epilepsy / Q000503:physiopathology / Q000628:therapy; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008564:Membrane Potentials / Q000528:radiation effects; D023421:Models, Animal; D009431:Neural Conduction / Q000528:radiation effects; D011817:Rabbits