Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
Low-level laser irradiation of visible light had been introduced as a medical treatment already more than 40 years ago, but its medical application still remains controversial. Laser stimulation of acupuncture points has also been introduced, and mast-cells degranulation has been suggested. Activation of TRPV ion channels may be involved in the degranulation. Here, we investigated whether TRPV1 could serve as candidate for laser-induced mast cell activation. Activation of TRPV1 by capsaicin resulted in degranulation. To investigate the effect of laser irradiation on TRPV1, we used the Xenopus oocyte as expression and model system. We show that TRPV1 can functionally be expressed in the oocyte by (a) activation by capsaicin (K(1/2) = 1.1 μM), (b) activation by temperatures exceeding 42°C, (c) activation by reduced pH (from 7.4 to 6.2), and (d) inhibition by ruthenium red. Red (637 nm) as well as blue (406 nm) light neither affected membrane currents in oocytes nor did it modulate capsaicin-induced current. In contrast, green laser light (532 nm) produced power-dependent activation of TRPV1. In conclusion, we could show that green light is effective at the cellular level to activate TRPV1. To which extend green light is of medical relevance needs further investigation.
Figure 1. Effect of capsaicin application on current-voltage curves. (a) Membrane current in oocytes injected with TRPV1-cRNA. Large open circles before, filled squares during, and small open circles after application of 500 nM capsaicin. (b) Capsaicine-induced current in uninjected oocytes (open circles) and cRNA-injected oocytes (filled squares). All data are averages from 8 experiments (±SEM).
Figure 2. Dependence of TRPV1-mediated current on capsaicin concentration. Filled squares current at −60 mV and open squares at −100 mV. Data are averages from 7 experiments (±SEM). Lines represent approximations of the concentration dependencies with the same K1/2 value of 1.06 μM.
Figure 3. Inhibition of capsaicin-induced current by RuR. Filled square current-voltage dependence of current induced by 500 μM capsaicin, filled circles in the simultaneous presence of 12 μM RuR. Data are averages (±SEM) of 14 measurements in the absence and of 4 measurements in the presence of RuR.
Figure 4. Effect of pH reduction on membrane current. Change current in response to a reduction of external pH from 7.4 to 6.2 in noninjected oocytes (open circles) and in cRNA-injected cells (filled squares). Data for injected cells are averages (±SEM) of 7 measurement; for the control cells 2 measurements were performed.
Figure 5. Effect of elevated temperature on membrane current of TRPV1-expressing oocytes. (a) Effect of 42°C (filled circles) in comparison to 25°C before and after the raise in temperature. (b) Effect of 35°C (filled circles) in comparison to 25°C before the raise in temperature and to the current induced by 500 nM capsaicin (filled squares).
Figure 6. Effect of red laser light on current-voltage curve of TRPV1-mediated current. TRPV1 was activated by 500 nM capsaicin. Open square were obtained before irradiation, filled circles at the end of a 2 min lasting irradiation period (637 nm, 36 mW), and open circles 2 min after the laser light was turned off. Data represent averages from 3 oocytes (±SEM).
Figure 7. Effect of blue laser light on current-voltage curve of TRPV1-mediated current. TRPV1 was activated by 500 nM capsaicin. Open square were obtained before irradiation, filled circles at the end of a 2-min lasting irradiation period (406 nm, 5 mW), and open circles 2 min after the laser light was turned off. Data represent averages from 3 oocytes (±SEM).
Figure 8. Effect of green laser light on current-voltage curve of TRPV1-mediated current. (a) Light-activated current in oocytes injected with cRNA for TRPV1; output power 5 mW (circles), 10 mW (triangle up), and 20 mW (triangles down). Data represent averages from 3 oocytes (±SEM). (b) Membrane current before (open squares), during (2 min after light was turned on, filled circles), and after irradiation at 40 mW. Data represent averages from 5 oocytes (±SEM).
Figure 9. Pen recording of holding current at −60 mV. Downward deflexions represent activation of inward current. Red light of 637 nm was applied at 36 mW, green light of 532 nm at 40 mW, and blue light of 406 nm at 5 mW.
Figure 10. Degranulation of human mast cells induced by capsaicin. (a) Human mast cells HMC-1 incubated in bath solution in the absence of the TRPV1-specific agonist capsaicin. (b) HMC-1 cells having been superfused for 5 min with bath solution containing 1 μM capsaicin. The arrows point to the degranulating cell. (c) Percentage of degranulated HMC-1 cells in the absence and presence of 500 nM capsaicin (exposition time 10 min, values present averages of 3 independent experiments ±SEM).
Abraham,
TRPV1 expression in acupuncture points: response to electroacupuncture stimulation.
2011, Pubmed
Abraham,
TRPV1 expression in acupuncture points: response to electroacupuncture stimulation.
2011,
Pubmed
Anderson,
The optics of human skin.
1981,
Pubmed
Caterina,
Impaired nociception and pain sensation in mice lacking the capsaicin receptor.
2000,
Pubmed
Caterina,
The capsaicin receptor: a heat-activated ion channel in the pain pathway.
1997,
Pubmed
,
Xenbase
Chow,
Inhibitory effects of laser irradiation on peripheral mammalian nerves and relevance to analgesic effects: a systematic review.
2011,
Pubmed
Dumont,
Oogenesis in Xenopus laevis (Daudin). I. Stages of oocyte development in laboratory maintained animals.
1972,
Pubmed
,
Xenbase
Gao,
Sino-European transcontinental basic and clinical high-tech acupuncture studies-part 3: violet laser stimulation in anesthetized rats.
2012,
Pubmed
García-Martínez,
Identification of an aspartic residue in the P-loop of the vanilloid receptor that modulates pore properties.
2000,
Pubmed
,
Xenbase
Karu,
Primary and secondary mechanisms of action of visible to near-IR radiation on cells.
1999,
Pubmed
Karu,
A novel mitochondrial signaling pathway activated by visible-to-near infrared radiation.
2004,
Pubmed
Langevin,
Biomechanical response to acupuncture needling in humans.
2001,
Pubmed
Langevin,
Evidence of connective tissue involvement in acupuncture.
2002,
Pubmed
Langevin,
Connective tissue: a body-wide signaling network?
2006,
Pubmed
Litscher,
Integrative laser medicine and high-tech acupuncture at the medical university of graz, austria, europe.
2012,
Pubmed
Mester,
The biomedical effects of laser application.
1985,
Pubmed
Raisinghani,
Activation of transient receptor potential vanilloid 1 (TRPV1) by resiniferatoxin.
2005,
Pubmed
,
Xenbase
Shen,
Effect of combined laser acupuncture on knee osteoarthritis: a pilot study.
2009,
Pubmed
Vennekens,
Vanilloid transient receptor potential cation channels: an overview.
2008,
Pubmed
Vriens,
Pharmacology of vanilloid transient receptor potential cation channels.
2009,
Pubmed
Whittaker,
Laser acupuncture: past, present, and future.
2004,
Pubmed
Yang,
Effects of low power laser irradiation on intracellular calcium and histamine release in RBL-2H3 mast cells.
2007,
Pubmed
Zhang,
Role of mast cells in acupuncture effect: a pilot study.
2008,
Pubmed
Zhang,
Mast-cell degranulation induced by physical stimuli involves the activation of transient-receptor-potential channel TRPV2.
2012,
Pubmed