532 nm Low-Power Laser Irradiation Facilitates the Migration of GABAergic Neural Stem/Progenitor Cells in Mouse Neocortex.

Background And Objective: Accumulating evidence has shown that low-power laser irradiation (LLI) affects cell proliferation and survival, but little is known about LLI effects on neural stem/progenitor cells (NSPCs). Here we investigate whether transcranial 532 nm LLI affects NSPCs in adult murine neocortex and in neurospheres from embryonic mice.

Study Design/materials And Methods: We applied 532 nm LLI (Nd:YVO4, CW, 60 mW) on neocortical surface via cranium in adult mice and on cultured cells from embryonic mouse brains in vitro to investigate the proliferation and migration of NSPCs and Akt expression using immunohistochemical assays and Western blotting techniques.

Layer-specific modulation of neuronal excitability by 660-nm laser irradiation in mouse neocortex.

It has been reported that laser light irradiation (LLI) could regulate neuronal activities in the forebrain, but little is known if and how LLI in the red wavelength range affects neuronal excitability. Here, we investigated the effects of a continuous diode laser at 660 nm on intrinsic membrane properties and excitability of presumed pyramidal neurons in the thalamocortical input layer (layer 3/4) and in layer 5 of mouse primary auditory cortex using the whole-cell patch-clamp recording technique. In layer 3/4 neurons, 660-nm laser irradiation (LLI-660) at 20 mW for 5 min gradually increased resting membrane potentials, which reached a plateau after irradiation.

The effect of low-level laser irradiation on muscle tension and hardness compared among three wavelengths.

Background And Aims: It has been reported that low-level laser irradiation (LLLI) can influence muscle tissue by retarding attenuation of muscle tension. Since the efficacy of LLLI on the effects of muscle contraction remains unclear, we examined in an in vivo animal model whether LLLI affects both muscle tension and muscle hardness in a wavelength-dependent manner, using the rat gastrocnemius muscle.

Material And Methods: Forty Sprague-Dawley adult rats were used.

532 nm low-power laser irradiation recovers γ-secretase inhibitor-mediated cell growth suppression and promotes cell proliferation via Akt signaling.

Background And Objective: The γ-secretase inhibitor (GSI) has been shown to inhibit expression of amyloid beta (Aβ), but GSI also has a side effect of reducing cell survival. Since low-power laser irradiation (LLI) has been known to promote cell survival, we examined whether 532 nm LLI can rescue the GSI side effect or not.

Study Design/materials And Methods: The human-derived glioblastoma cells (A-172) were cultured in 35 mm culture dishes or 96-well plate.

Spectral analysis of bilateral or alternate-site kindling-induced afterdischarges in the rabbit hippocampi.

Kindling is one of the popular animal models of temporal lobe epilepsy. In the present study following the previous results obtained using unilateral hippocampal kindling (UK), we performed spectral analysis of bilateral or alternate-site kindling-induced afterdischarges (ADs) in the rabbit hippocampi. Eight and ten adult rabbits were used for bilateral kindling (BK) and alternate-site kindling (AK), respectively.

Immunocytochemical studies on the effect of 405-nm low-power laser irradiation on human-derived A-172 glioblastoma cells.

The application of low-power laser irradiation (LLI) affects the cell cycle and cell proliferation in various kinds of cells. LLI at a wavelength of 808 nm and a power of 30 mW has been found to significantly decrease the proliferation rate of cells of the human-derived glioblastoma cell line A-172. To determine if this effect of LLI is specific to 808-nm LLI, the present study was designed to reveal the effects of 405-nm LLI under the same experimental conditions.

Low-power 808-nm laser irradiation inhibits cell proliferation of a human-derived glioblastoma cell line in vitro.

It has been reported that low-power laser irradiation (LLI) can modulate various biological processes including cell proliferation. Some reports suggest that LLI interferes with the cell cycle and inhibits cell proliferation, while others suggest that LLI has a stimulatory effect. Mechanisms underlying the effects of LLI remain unclear.

Fast Fourier transformation analysis of kindling-induced afterdischarge in the rabbit hippocampus.

Kindling is a widely used animal model of intractable temporal lobe epilepsy. In the present study, we performed fast Fourier transformation (FFT) analysis of kindling-induced afterdischarge (AD) in the rabbit hippocampus. Ten adult rabbits were used.

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.

Effects of 808 nm low-power laser irradiation on the muscle contraction of frog gastrocnemius.

Background And Objectives: The efficacy of low-power laser irradiation (LLI) on muscle fibers remains unclear; therefore, we examined the effect of LLI (808 nm: 60 or 100 mW) on muscle contraction and conducted waveform analyses of the twitch curve, including alterations in the peak amplitudes of tension (AMP), latency (LAT), contraction period (CP), and relaxation period (RP).

Study Design/materials And Methods: The sciatic nerve-gastrocnemius muscles of 35 frogs (Xenopus laevis) were prepared. In Experiment 1, continuous stimulation for gastrocnemius contraction was delivered to the sciatic nerve (10 minutes); the experimental group simultaneously received LLI.

Effects of the Ih blockers CsCl and ZD7288 on inherited epilepsy in Mongolian gerbils.

The h current (Ih) is an inwardly mixed cationic conductance activated by membrane hyperpolarization. We previously demonstrated that the Ih blockers CsCl and ZD7288 can significantly increase the threshold of electrically induced paroxysmal discharge in the rabbit hippocampus. In the present study, we examined the effects of these Ih blockers on inherited epilepsy in Mongolian gerbils.

Effects of hyperpolarization-activated channel blocker ZD7288 on polar excitations of frog sciatic nerve.

Previous studies have demonstrated that Ar(+) laser irradiation shows a more selective blocking effect on the generation of anode-break-excitation (AE) than on cathode-make-excitation (CE), and that the effects of laser irradiation closely resemble those following the application of hyperpolarization-activated current (Ih) blocker, ZD7288. We therefore examined the effects of ZD7288 and tetrodotoxin (TTX) on polar excitations to reveal whether such a selective effect of ZD7288 on AE is specific in frog sciatic nerve. Supramaximal stimuli (10-ms pulse) were applied while for 30 min each channel blocker was applied to the stimulating sites.

Effects of argon laser irradiation on polar excitations in frog sciatic nerve.

Background And Objectives: 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.

Study Design/materials And Methods: Using 43 frogs (Xenopus laevis), nerve preparations were stimulated at 0.5/second using a 10-millisecond pulse at supramaximal intensity.

Epileptogenesis induced by alternate-site kindling in bilateral hippocampi.

Purpose: Alternate-site kindling (AK), which has been known to induce so-called kindling antagonism, was performed in the bilateral hippocampi to reveal neural mechanisms underlying hippocampal kindling.

Methods: Ten adult rabbits were used. Daily kindling stimulation consisted of a 1- s train of 50 pulses (pulse duration, 1 ms) of 80 to 200 microA (base-to-peak), which was higher than the afterdischarge (AD) threshold.

Ih blockers have a potential of antiepileptic effects.

Purpose: The h current (Ih) is an inwardly mixed cationic conductance activated by membrane hyperpolarization and distributed predominantly in the apical dendrites of hippocampal pyramidal neurons. To verify a hypothesis that an anomalous hyperpolarization generates an abnormal excitation by way of Ih channels, we examined the effects of Ih blockers (CsCl and ZD7288) on electrically induced paroxysmal discharges (PADs).

Methods: Fifty-three adult male rabbits were used.

The extracellular current blocking effect of cesium chloride on the theta wave in the rabbit hippocampal CA1 region.

We studied the extracellular effects of cesium chloride (CsCl), a blocker of the hyperpolarization-activated cationic current (I(h)), on the hippocampal theta wave in pentobarbital-anesthetized rabbits. We recorded spontaneous field potentials at the hippocampal CA1 region before and at three time periods after CsCl or saline injections. We found that CsCl injected into the apical dendritic layer attenuated the theta wave amplitude.