We investigated diode laser (980 nm) evoked activation of transient receptor potential proteins (TRPV1 and TRPV2). C and A-delta (A&dgr;) nociceptor families are primarily responsible for pain mediation in the peripheral nervous system. TRPV1 proteins have been associated with heat evoked pain in C fibers while A&dgr; fibers have been associated with TRPV2. Diode laser stimulation allows a margin of safety between non-invasive activation and damage <sup>19, 22, 34</sup>. Laser pulses (20-50 ms, 0.1-10 W, 980 nm) were used to stimulate: A) in vitro: excised patches from HEK293 cells expressing TRPV1; B) <i>in vitro</i>: rat DRG nociceptors expressing either TRPV1 or TRPV2; and C) <i>in vivo</i>: C-fibers of the rat saphenous nerve (SN) trunk. Cell currents were recorded using standard patch clamp methods. The SN was also stimulated electrically with bipolar electrodes. Stimulation (20-50 ms) of HEK and DRG cells expressing TRPV1 was highly reproducible. Activation and peak currents were achieved at estimated peak temperatures of 55°C and 70°C. Threshold activation was also observed in DRG neurons expressing TRPV2. The conduction velocity for laser-activated saphenous nerve afferents was in the C fiber range (0.5-1 m/s). Electrically stimulated nerve contained stimulation artifacts and complex neural components with conduction velocities ranging from 0.3-30 m/s. Diode laser activation of TRPV1 protein is a reproducible and effective means to probe TRP activity in both <i>in vivo</i> and <i>in vitro</i> preparations
An analysis of the applicability of multimode laser diodes (LDs) in holography is presented. Coherence properties of the two most probable regimes of multimode operation, free- running and phase locked, are analyzed. Prospectives of the use of multimode LDs in recording deep holograms are estimated theoretically and experimentally.
Criteria for the applicability of multimode laser diodes (LDs) with total emission spectra as broad as 10-30 A in holography are considered. Coherence properties of the two most probable regimes of multimode operation, free-running and phase locked, are analyzed. Prospectives of the use of multimode LDs in recording deep holograms are estimated theoretically and experimentally.
Four-hundred-forty-one nm and 1060 nm wavelength laser irradiation caused specific skin pain and warmth sensations. The reasons allowing skin pain sensations at the 441 nm laser irradiation and warmth sensations at the 1060 nm laser irradiation are discussed.
Laser ((lambda) equals 0.630 micrometers , 1 - 3 mW/cm<SUP>2</SUP> with exposition 10 min) was used to investigate the influence of laser irradiation on rat platelet functional activity. It was determined that irradiation of thrombocyte enriched plasma caused increase of ADP-induced thrombocytes aggregation. Disaggregation process was not influenced considerably by this irradiation.
The action of laser radiation on arbitrary selected points of skin in the wavelength range 440 - 1060 nm and power range 40 mW - 4 W caused threshold and near threshold skin sensations. The warm sensations and skin pain were observed. The skin pain sensations are probably related to the radiation action on free nerve endings in the epidermis (specific skin pain) or upon the receptor system situated under the epidermis (nonspecific skin pain). The warm sensations are related to the radiation action on temperature-sensitive points of skin. The dependence of stimulus intensity on its duration for the threshold thermal sensations was revealed.