Laser irradiation of the rat cranium can produce analgesia. The present experiment investigated the mechanism of such action. 27 rats received all possible combinations of laser (0, 6.4, and 12J/cm2) and naloxone (0, 5, and 10 mg/kg) prior to a hot plate test. Laser (820 nm, KHz pulsing, Omega Laser Systems, London) was applied to the rats' skulls and hind paw lick latencies (in seconds) were recorded immediately, 30 min., and 24 hr. after the administration of treatment. When animals were rested immediately following laser irradiation at 12J/cm2 significant analgesia resulted. Treatment with naloxone at either dose antagonised this effect, but naloxone produced no significant hyperalgesia when given alone. This suggests that opioid peptide mechanisms mediate the analgesic action of low-intensity laser irradiation of the cranium.
Get full access to this article
View all access options for this article.
References
1.
AkilM.MayerD. J., & LiebeskindJ. C. (1976) Antagonism of stimulation produced analgesia by naloxone, a narcotic antagonist. Science, 191, 961–962.
2.
BasfordJ. R. (1989) Low energy laser therapy: controversies and new research findings. Lasers in Surgery and Medicine, 9, 1–5.
3.
ChapmanR. C., & BenedettiC. (1977) Analgesia following transcutaneous electrical nerve stimulation and its partial reversal by a narcotic antagonist. Life Sciences, 2, 1645–1648.
4.
ChoiJ. J.SrikanthaK., & WhuW-H. (1986) A comparison of electroacupuncture, transcutaneous electrical nerve stimulation and laser photobiostimulation on pain relief and glucocorticoid secretion. International Journal of Acupuncture and Electrotherapeutics Research, 11, 45–51.
5.
EddyN. B., & LeimbachD. (1953) Synthetic analgesics: II. Didiienylbutenyl and pithienylbutylamines. Journal of Pharmacology and Experimental Therapeutics, 107, 385–393.
6.
LombardA.RossettiV.CassoneM. C.UrciuoliR., & RolfoP. M. (1991) Neurotransmitter content and enzyme activity variations in rat brain following in vivo He-Ne laser irradiation. In PassarellaS.QuagliarelloE., & JorG. (Eds.), Round table on basic and applied research in photobiology and photomedicine.Bari, Italy: Bayer. Pp. 6.
7.
LoweA. S.BaxterG. D.WalshD. M., & AllenJ. M. (1993) The effect of low intensity laser irradiation upon conduction and skin temperature in the human median nerve. Lasers in Surgery and Medicine, 5, 8.
8.
MayerD. J.PriceD. D., & RafiiA. (1977) Antagonism of acupuncture analgesia in man by the narcotic antagonist naloxone. Brain Research, 121, 368–372.
9.
MelzackR., & WallP. (1988) The challenge of pain. (2nd ed.) London: Penguin.
10.
PikulevA. T.ZynanovaT. N.LavrovaV. M.MostovnikovV. A., & KhohlovI. V. (1985) Effect of local laser irradiation on the activity of some enzymes of glutamic acid metabolism in rat tissue. Radiobiologiia, 35, 678–680.
11.
PomeranzB., & ChiuD. (1976) Naloxone blockade of acupuncture analgesia: endorphins implicated. Life Sciences, 19, 1757–1762.
12.
PonnuduraiR. N.ZbuzekV. K., & WuW. (1987) Hypoalgesic effect of laser photobiostimulation shown by rat tail Hick test. International Journal of Acupuncture and Electrotherapeutics Research, 12, 93–100.
13.
ShenZ.XiaoJ.LinS. Z., & WangL. H. (1982) Effects of low power laser beam guided by optic fibre on rat brain striatal mono-amines and amino acids. Neuroscience Letters, 32, 203–208.
14.
ViziE. S.MesterE.TiszaS., & MesterA. (1977) Acetylcholine effects of laser irradiation to Auerbach plexus in guinea pig ilium. Journal of Neural Transmission, 40, 305–308.
15.
WalkerJ. (1983) Relief from chronic pain by low power laser irradiation. Neuroscience Letters, 43, 339–344.
16.
WedlockP. M. (1995) Behavioural effects of low intensity laser irradiadon of the rodent brain. Unpublished D.Phil. thesis, University of Ulster.
17.
WedlockP. M.ShephardR. A.AllenJ. M., & BaxterG. D. (1993) Analgesia with crania) laser irradiation in rats is reversible with naloxone. Irish Journal of Medical Science, 162, 387.
18.
WedlockP. M.ShephardR. A.LittleC.McBurneyF. (in press) Analgesic effects of cranial laser treatment in two rat nociception models. Physiology and Behavior.
19.
WoolfeC., & MacDonaldA. D. (1944) The evaluation of the analgesic action of pethidine hydrochloride (Demerol). Journal of Pharmacology and Experimental Therapeutics, 80, 300–307.
20.
ZarkovicN.ManevH.PericicD.SkalaK.JurinM.PersinA., & KubovicM. (1989) Effect of semiconductor GaAs laser irradiation on pain perception in mice. Lasers in Surgery and Medicine, 9, 63–66.
21.
ZynanovaT. N.LavrovaV. M.PikulevA. T., & KhripchenkoI. P. (1987) Catecholamine content and acetylcholinesterase activity in rat brain affected by laser radiation. Radiobiologiia, 227, 94–97.
