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Purpose: To determine the correlation between functional parameters and optical coherence tomography (OCT) features in patients of idiopathic intracranial hypertension (IIH). Methods: A prospective observational study in early and established cases of papilledema in IIH presenting from December 2017 to February 2019. Functional parameters (visual acuity, contrast sensitivity, mean deviation, VER, and MfERG) and structural parameters (RNFL, GCL?IPL, and optic disc height) were measured at baseline and every 6 weeks for 6 months. Results: At baseline, average RNFL had a moderate negative correlation with mean deviation (r = ?0.45; P = 0.0007) and a positive correlation with logMAR visual acuity (r = 0.18; P = 0.17). On the contrary, baseline GCL and logMAR visual acuity had a negative correlation (r = ?0.4, P = 0.02). Optic disc height (ODH) had a negative correlation with visual field mean deviation (r = ?0.046; P = 0.0005). At 6 months, ODH and GCL?IPL complex had a statistically significant correlation with functional parameters. However, RNFL values did not show any significant correlation with any of the functional parameters. Baseline GCL?IPL and optic disc height values had a moderate and significant correlation with final functional parameters. However, RNFL did not show any correlation with final functional parameters. Correlation between GCL?IPL thickness at 6 weeks and final functional parameters were stronger than that with baseline GCL values. Conclusion: In the setting of severe papilledema, RNFL can misguide the prognosis. GCL?IPL can be a valuable tool for an objective evaluation of the integrity of the optic nerve in IIH and ODH may be used as an alternative or in combination with GCL?IPL in these cases.
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BACKGROUND: Melasma, a common chronic pigmentary disorder, is resistant to various treatments. Recently, pulse-in-pulse type of intense pulsed light (PIP IPL) has been introduced as a treatment for melasma. It can emit multiple peaks during one pulse wave to deliver photothermal energy more effectively with gentle and even low energy so that complications are minimal. OBJECTIVE: The purpose of this study was to compare the efficacy and safety of PIP IPL to low-fluence, multi-pass, Q-switched Nd:YAG laser in the treatment of facial melasma. METHODS: Fifteen female patients with melasma who had Fitzpatrick skin type III or IV were enrolled in this study between November 2014 and April 2015. Patients underwent 6 sessions of treatment at an interval of 1 week. One half of each patient's face was treated with 2 passes of PIP IPL with a fluence of 13~15 J/cm₂. The other half of the face was treated with 4 passes of Q-Switched Nd:YAG laser with a fluence of 1.6~1.8 J/cm₂. Results were evaluated at every visit, including modified Melasma Area and Severity Index (MASI) score, subject's global assessment, and investigator's global assessment. RESULTS: Modified MASI scores were significantly (p<0.05) reduced in both groups after 6 treatment sessions. Q-Switched Nd:YAG laser treatment was more effective than PIP IPL for the treatment of melasma, although the two treatments did not significantly (p=0.44) differ in effectiveness. However, the discomfort levels of patients in the PIP IPL group following procedures were significantly lower compared to those in the Q-Switched Nd:YAG group. CONCLUSION: The current investigation demonstrated that PIP IPL treatment for melasma in Korean women was not inferior to collimated low fluence Q-switched Nd:YAG laser treatment.
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Female , Humans , Melanosis , SkinABSTRACT
Objective To evaluate the combined treatment effect of intensive pulsed light (IPL,420 nm and 540 nm,by mode of 4+3) on acne vulgaris and acne erythem.Methods A total of 80 patients with acne vulgaris were divided randomly into the treatment and the control group.The treatment group including forty cases were first treated by 420 nm IPL for 4 times,and the interval was one week; and then treated by IPL 420 nm combined with 540 nm for 3 times,the interval was four weeks.The control group was just treated by Adapalene at every night for 16 weeks.Results The treatment efficiency of inflammatory lesion after 4 weeks showed that the effective rate in the treatment group was 65.0 ％ compared to 47.5 ％ in the control group,and the difference was statistically significant (P＜0.05).The treatment results of inflammatory lesion after 16 weeks showed that efficiency was 85％ in the treatment group,while 62.5％ in the control group,and difference was statistically significant (P＜0.05).The treatment results of acne erythem showed that the effective rate was 90 ％ in the treatment group,but 37.5 ％ in control group,there was statistically significant (P＜ 0.01) between the two groups.Conclusions Combined use of 420 nm and 540nm IPL by protocol of4+3 is an effective method for treatment of acne vulgaris and acne erythem.
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Intense pulsed light (IPL) is a high-intensity polychromatic incoherent light of a determined wavelength spectrum, fluence, and pulse duration. Clinicians can combine these variable factors of IPL for the purpose of selective destruction of target chromophores. Due to these properties, IPL has been widely used for numerous indications including hair removal and treatment of vascular or pigmented lesions. For skilled and experienced clinicians, IPL is a great treatment modality; however it can be a source of serious adverse effects when performed by untrained clinicians. Thus, to promote the proper and safe use of IPL, we summarized the origin, history, basic principles, and clinical application of IPL and discussed qualification factors needed for clinicians who use IPL.
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Hair RemovalABSTRACT
ObjectiveTo study the therapeutic effect of variable pulsed Nd∶YAG laser and intense pulsed light (IPL) on port wine stain(PWS) in an animal model.MethodsThe combs of 38 Leghorn chickens served as the animal model of PWS,which were randomly classified into 4 groups:blank control group receiving no irradiation,Nd:YAG group receiving Nd∶YAG laser irradiation for 2 sessions,IPL group receiving IPL irradiation for 2 sessions,and combination group receiving 1 session of Nd∶YAG laser irradiation followed by 1 session of IPL irradiation 45 days later.One week after the final irradiation,the rnorphology of combs was observed,and tissue specimens were resected from the combs for the analysis of histological changes and blood vessel density.The data were assessed by using one-way ANOVA.ResultsAfter 2 sessions of irradiation,the color of comb skin was lightened,and light microscopy showed the thickening of vascular layers in the dermis,blockage of blood vessels and decrease in the number of blood vessels.The count of blood vessels per high power field(× 400) was significantly lower in the Nd∶YAG group(17.92 ± 3.63),IPL group(8.08 ± 1.56)and combination group(7.08 ± 1.31) than in the control group(37.08 ± 3.97,all P ＜ 0.01 ),but was similar between the combination group and IPL group (P ＞ 0.01),and higher in the Nd∶YAG group than in the combination group(P ＜ 0.01 ).ConclusionsVariable pulsed Nd∶YAG laser and IPL,alone or in combination,can be used in the treatment of PWS,however,the effect of IPL alone or in combination with Nd:YAG seems superior to that of Nd∶YAG laser alone.
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Objective To study the effect of multiple IPL treatment on cell senescence markers of skin fibroblasts using UVA as a control and to make clear whether the multiple IPL treatment may result in cell senescence.Methods Cells were divided into three groups: one group without irradiation as a control,one group receiving IPL treatment with 15 J per cm2,and the last group receiving UVA irradiation with 9 J per cm2.IPL and UVA irradiation were performed once a day during five days.On the sixth day,the cells were collected.Senescence-associated β-galactosidase (SA-β-Gal) staining,cell cycle,reactive oxygen species (ROS) and telomere length were determined.Results Our results showed that five consecutive days of IPL irradiation had no effect on the activity of SA-β-Gal and telomere length and decreased the G1 ％ of cell cycle and the level of ROS in comparison with the control group (P＜0.05).On the contrary,five consecutive days of UVA irradiation increased the activity of SA β Gal and the level of ROS,shortened the length of telomere and no obvious change in the G1 ％ of cell cycle in comparison with the control group.Conclusions Multiple UVA irradiations induce cell senescence.On the contrary,multiple IPL treatments could not induce cell senescence.
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BACKGROUND: Recently, low fluence collimated Q-switched (QS) Nd:YAG laser has drawn attention for the treatment of melasma. However, it needs a lot of treatment sessions for the substantial results and repetitive laser exposures may end up with unwanted depigmentation. OBJECTIVE: We evaluated the clinical effects and safety of the combinational treatment, using intense pulsed light (IPL) and low fluence QS Nd:YAG laser. METHODS: Retrospective case series of 20 female patients, with mixed type melasma, were analyzed using medical records. They were treated with IPL one time, and 4 times of weekly successive low fluence Nd:YAG laser treatments. At each visit, digital photographs were taken under the same condition. Melanin index (MI) and erythema index (EI) were measured on the highest point on the cheekbones. Modified melasma area and severity index (MASI) scores were calculated by two investigators using digital photographs. RESULTS: The mean values of MI and EI decreased significantly after treatments. The modified MASI score has decreased by 59.35%, on average. Sixty percents of the participants did not require any more treatments, and no clinical aggravations were observed during the follow-up period (mean 5.9 months). CONCLUSION: IPL and low fluence laser may elicit a clinical resolution in the mixed type melasma with long term benefits.
Subject(s)
Female , Humans , Erythema , Follow-Up Studies , Light , Medical Records , Melanins , Melanosis , Research Personnel , Retrospective StudiesABSTRACT
Objective To study the protective effects of intense pulse light (IPL) on the injury of normal human skin fibroblasts (FB) induced by ultraviolet A (UVA Ⅰ ) in vitro and to explore its possible mechanism. Methods The human skin fibroblasts were isolated and cultured, and then irradiated by UVA Ⅰ (9 J/cm2) and IPL (15 J/cm2), respectively. The proliferative ability of the cells were detected by CCK-8. Cell cycle was detected by flow cytometry, and cylin D1 and CDK2 protein expression levels were detected by Western blot. Results Different doses of UVA Ⅰ irradiation caused certain damages of cultured fibroblasts. With the increasing of of UVA Ⅰ dose, cell proliferation was decreased. Cells went to death at the exposure to 11 J/cm2 UVA Ⅰ , while the proliferative activity did not change much at 7 J/cm2 UVA Ⅰ . Cells were treated with UVA Ⅰ for other 2 days, then with IPL irradiation for other 2days, showing clear stimulating to the cell proliferation as compared with the cells that received UVA Ⅰ treatment only. Flow cytometry results showed that an increase of cell proliferating index, and cell cycle protein cyclin D1 and CDK2 expression levels were also upregulated after IPL irradiation.Conclusion UVA Ⅰ irradiation may cause cell damage as showed by cell growth index, cyclin D1 and CDK2 expression, and this injury could be protected partly by IPL treatment. The intense pulsed light may regulate the expression of cyclin proteins that may promote normal fibroblast proliferation, which could be one of the mechanisms of IPL skin rejuvenation.
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Intense pulsed light (IPL) is a high-intensity pulsed light source emitting polychromatic, non-coherent, and defocused light with a broad wavelength spectrum. However, IPL can similarly work as a conventional laser with the help of variable cut-off filters. It enables selective destruction of target chromophores based upon the theory of selective photothermolysis. Clinicians can combine variable factors including wavelengths, pulse durations, and fluences in IPL systems, which allow great versatility in treating wide ranges of dermatologic diseases and flexibility in optimizing individual treatment parameters according to different skin types or indications. These properties are of great advantage for skilled and experienced clinicians but can be a source of unwanted serious adverse effects for untrained ones at the same time. Therefore, we summarized the basic principles and clinical application of IPL devices to provide the practical guidance. In addition, critical diagnostics, a great deal of experience, and a thorough knowledge of skin pathology and physiology are required for an effective and safe IPL treatment.
Subject(s)
Enzyme Multiplied Immunoassay Technique , Imidazoles , Light , Nitro Compounds , Pliability , SkinABSTRACT
Objective To explore the treatment outcomes of intensive pulsed light (IPL) in combinationwith rb-bFGF in patients with telangiectasia.Methods A total of 57 patients with telangiectasia were randomly divided into 2 groups:group A,IPL540nm (n=32);group B,IPL with rb-bFGF (n=25).The intense pulsed light with 540 nm wavelength,energy density of 14-17 J/cm2 and pulse width of 10-12 ms was used for 3-5 times at intervals of 4-5 weeks.Results Fifty-seven patients completed the Study with maximal 5 treatment sessions,100% improvement was observed in 15.62% and 64.00% at group A and group B respectively after 1-2 treatment sessions,but in 62.5% and 84% after 3-4 treatmentsessions.There was significant difference in treatment sessions between the groups A and B (P<O.05).Only 5 cases were observed transient pigmentation on the face during the follow-up period of 6 month,but resolved later.Conclusion IPL in combination with rb-bFGF is an effective method for the treatment of faeial telangiectasia.
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Objective To compare the improvement of peri-orbita rhytides and the patients' satisfaction treated by intense pulse light, Elos and activeFXTM fractional CO2 laser. Methods Two groups of the study were conducted. In first group, 42 volunteers in the hospital were enrolled. All were took photos to evaluate the peri-orbita rhytides by the physician before and one month after activeFX? treatment. Doctors and volunteers evaluated the improvement of peri-orbita rhytides and satisfaction together. In second group, a retrospective study was conducted, in which 40 patients were treated with intense pulse light, and other 40 patients treated with Elos in 2006-2007. Their improvements were analyzed through comparison of their photos before and one month after treatment, and the satisfaction was also evaluated. All data were analysed by SPSS10. 0. Results ActiveFXTM fractional CO2 laser is better than other two techniques for improving peri-orbita rhytides, and patients were more satisfied with this technology. Conclusion The improvement of peri-orbita rhytides and satisfaction treated by activeFXTM is higher than intense pulse light and Elos techniques.
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Objevtive To evaluate the efficacy and safety of intensive pulse light (IPL) on treating the telangiectasis and dermal atrophy due to corticosteroid-dependent dermatitis.Methods We applied the IPL on 13 patients who had telangiectasis and dermal atrophy caused by corticosteroid-dependent dermatitis every three to four weeks.The treatment lasted three to eight times.The patients's skin types were Fitzpatrick Ⅲ-V and they had had corticosteroid therapy from 15 months to 13 years.Results To telangiectasis,3 patients had excellent effect afterwards;7 patients achieved fair good effect;Another patients also achieved improvement;2 cases had no positive effect;The total effective rate reached 76.92%.10 patients of dermal atrophy among the total 13 had improvement of the thickness of dermis.Conclusion Intensive pulse light can improve the telangiectasis and dermal atrophy of corticosteroid-dependent dermatitis.It needs less recovery time with fewer side effects and therefore IPL is an effective method for the Iesions.
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Introdução: Manchas vinho do Porto (MVP) são malformações vasculares presentes ao nascimento que podem causar alterações emocionais no paciente conforme sua localização. Tratamentos com luz intensa pulsada (LIP) e outros tipos de lasers têm sido relatados com respostas variadas. Objetivos: Revisão da literatura sobre opções terapêuticas utilizando fontes de luz nas MVP e demonstração de tratamento bem-sucedido com LIP associada a laser Nd:YAG. Método: Paciente feminina, de 14 anos, apresentando MVP na região supralabial foi tratada com a associação de laser Nd:YAG 1064nm e LIP 560nm. Foram realizadas 8 sessões com, em média, 30 dias de intervalo entre elas. Estudo realizado na Clínica Dermatológica Célia Kalil. Resultado: A paciente obteve total desaparecimento da MVP na área tratada, com o mínimo de efeitos adversos. Conclusão: A associação de LIP 560nm e laser Nd:YAG 1064nm parece ser uma alternativa adequada no tratamento das MVP.
Introduction: Port wine stains (PWS) are vascular malformations present at birth, and, depending on their location, they can cause emotional changes in the patient. Studies on the treatment of PWS with intense pulsed light (IPL) and other types of lasers presented different responses. Objectives: The objective of this study was to review the literature on the treatment options of PWS with light sources, demonstrating the success of IPL associated with Nd:YAG laser. Method: A 14 years old female patient with PWS in the supralabial region was treated with the association of 1064- nm Nd:YAG laser and 560-nm IPL. She underwent eight treatment sessions with a mean interval of 30 days between each session. The study was conducted at the Célia Kalil Dermatology Clinic. Result: The port wine stains disappeared completely with a very low incidence of adverse events. Conclusion: The association of 560-nm IPL and 1064-nm Nd:YAG laser seemed an adequate treatment alternative for PWS.
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BACKGROUND: Recently, the 2nd generation IPL with a filtered xenon flash lamp has been widely used in the dermatologic field. In disagreement with the manufacturer's intent, for Asian skin, there were some reports that the best results for vascular lesions were obtained with the PR applicator, while the best results for pigmented lesions were obtained with the VL applicator. OBJECTIVE: The purpose of this study is to compare the efficacy and safety of two different (530~750 nm PR applicator and the 555~950 nm VL applicator) wavelength bands of 2nd generation IPL in Korean photo-rejuvenation. In addition, we compared the improvement of telangiectasia, irregular pigmentation, and overall patient' satisfaction for both settings. METHODS: Twenty-two patients with signs of photoaging skin including irregular pigmentation and telangiectasia were treated with 2nd generation IPL (Ellipse-Flex(R), DDD, Denmark) using a split-face comparative method, comparing both sides with respect to improvement of telangiectasia, irregular pigmentation, and overall patient satisfaction. RESULTS: Comparison of the efficacy and safety between the VL and PR applicators revealed that the VL applicator was not specific for vascular lesions and that the PR applicator was not specific for pigmented lesions. Additionally, VL is not better than PR for vascular lesions (p=0.80, McNemar test) and PR is not better than VL for pigmented lesions (p=0.80, McNemar test). Finally, improvements in skin texture were not significantly different between VL and PR (p=0.80, McNemar test). CONCLUSION: The two IPL wavelength bands were found to be effective in the treatment of photo-damaged facial skin. The difference between the two treatment procedures with regard to clinical efficacy and safety was not significant.
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Humans , Asian People , Dichlorodiphenyldichloroethane , Pigmentation , Skin , Telangiectasis , XenonABSTRACT
Objective To assess the efficacy and safety of intensive pulse light (IPL) device for facial rejuvenation and the treatment of hyperpigmented lesions, facial telangiectasias, acne vulgaris and hair removal. Methods One hundred females who claim to improve their skin texture, hair re-moval and patients with hyperpigmented lesions, facial telangiectasias and acne vulgaris were treated with IPL device. Patients received five treatments with the time interval of 3 weeks to 1 month. Pho-tographs were assessed 1 month after the last treatment. Results For facial skin texture, the total im-provement were scored 100 %. For hyperpigmented lesions and facial telangiectasias, the total im-provement reached to 90%. For ache vulgaris, the total improvement reached to 75 %. For hair re-moval, the total improvement was 95 %. Conclusion The IPL device is an effective and safe modality for the improvement of skin texture, hyperpigmented lesions, facial telangiectasias and hair removal, and a novel modality for the treatment of acne vulgaris.
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BACKGROUND: Hypertrophic scars and keloids are prevalent and emotionally debilitating dermatologic diseases. Various treatment modalities have been advocated to treat hypertrophic scars and keloids. OBJECTIVE: This study prospectively assessed the safety and efficacy of using intense pulsed light (IPL) on scars that originate from surgery. METHODS: A total 22 patients with surgically induced hypertrophic scars and keloids were treated with IPL. Treatment was administrated at 4-week intervals, with an average of 3.5 sessions (range=1~10). The scars were evaluated for pigmentation, pliability, height, vascularity, pain and pruritus by using the modified Vancouver Scar Scale (MVSS). The subjective assessment of satisfaction was scored by the patients on a 25% increment of satisfaction scale. Evaluations were performed monthly during the follow-up period. RESULTS: There was overall clinical improvement for the appearance of the scars. Although statistically significant improvement was not shown (p=0.47), the average MVSS showed a trend for favorable effects on the scars with the successive IPL treatments. The patients who had higher baseline MVSS (> or =10) demonstrated statistically significant improvements with the successive IPL treatments (p<0.05). The degree of the patient's satisfaction also improved with the treatment for all of the patients (p<0.05). The adverse effects were negligible. CONCLUSION: IPL is one of the effective, safe methods to improve the clinical appearance of surgically induced hypertrophic scars and keloids and this treatment had high patient satisfaction and relatively few side effects.
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Humans , Cicatrix , Cicatrix, Hypertrophic , Follow-Up Studies , Keloid , Light , Patient Satisfaction , Pigmentation , Pliability , Prospective Studies , PruritusABSTRACT
Pilonidal sinus (PS) is one of follicular occlusion tetrad, and this is a chronic inflammatory disease that's characterized by a sinus or cyst with entrapped hair in the midline of the sacral region. The exact pathogenesis of PS remains unknown, but hair insertion may be the essential cause of the disease. PS is usually treated by surgical excision, marsupialization or incision and curettage. However, these surgical options often exhibit high recurrence rate, and especially for hirsute patients. Laser epilation has recently been recommended as an effective postoperative adjunctive therapy for PS and this treatment may reduce recurrence of PS. We report here on a 37-year-old male patient with PS, and the PS was treated by surgical excision and postoperative intense pulsed light (IPL) epilation.
Subject(s)
Adult , Humans , Male , Curettage , Hair , Hair Removal , Light , Pilonidal Sinus , Recurrence , Sacrococcygeal RegionABSTRACT
BACKGROUND: Acne vulgaris is one of the most prevalent and emotionally debilitating dermatologic diseases. Emerging problems with conventional acne treatments, such as the resistance of Propionibacterium acnes to antibiotics and the safety of oral isotretinoin, create a demand for other treatment modalities for acne. An evolving understanding of the Propionibacterium acnes-produced porphyrins and the development of a number of light sources have led to the application of photodynamic therapy for the treatment of acne. OBJECTIVE: To study the effect of light therapy on the treatment of Acne Vulgaris using acne mode intense pulsed light (IPL), and photodynamic therapy with a combination of topical 5-Aminolevulinic acid (ALA, 20%) and acne mode IPL. A comparison of the two treatment modalities would then be made to examine the effect on inflammatory acne lesions and sebum excretion. METHODS: Thirteen patients with varying degrees of acne were included in the study after a 4 week washout period. ALA (20%) was applied to half of the face on each patient. After one hour, the whole face was exposed to intense pulsed light (DECA(R), Italia) using an acne mode (400~1,200 nm) starting at a fluence of 11 J/cm(2). The procedure was carried out three times with 2 week intervals, and the patients were evaluated on post-op 2nd, 4th, and 6th weeks. Histologic changes were observed before and after treatment. RESULTS: After the first and second treatment, there was a statistically significant reduction in inflammatory acne lesion counts and the amount of sebum production from baseline, in both the ALA-PDT group and the IPL group (p<0.05). However, no statistically significant reduction was shown after the third treatment in both groups. There was a slightly higher reduction in the count of inflammatory lesions and the amount of sebum production in the ALA-PDT site compared to the IPL site, but it was not statistically significant. On histologic examination, dermal inflammatory cell infiltrations around the perivascular and periappendageal area were significantly reduced and sebaceous glands became smaller after the 3rd treatment. The adverse effects were negligible. CONCLUSION: ALA-PDT using acne mode IPL, and light therapy using acne mode IPL alone were effective in the reduction of inflamed lesions and sebum secretion in patients with mild to moderate acne vulgaris. Furthermore, no significant adverse effects were observed with both treatments. However, no remarkable contrast of therapeutic effect was statistically observed between the two therapies either.
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Humans , Acne Vulgaris , Anti-Bacterial Agents , Isotretinoin , Photochemotherapy , Phototherapy , Porphyrins , Propionibacterium , Propionibacterium acnes , Sebaceous Glands , SebumABSTRACT
BACKGROUND: The intense pulsed light (IPL) system is a high-intensity pulsed light source which emits noncoherent, defocused, polychromatic light is a broad wavelength spectrum of 400-1200 nm. The mechanism of action of the light system corresponds to selective photothermolysis. Nowaday, the IPL system is widely used in the dermatologic field for the removal of unwanted hairs, epidermal melanocytic lesions, vascular lesions, and for photorejuvenation. OBJECTIVE: The purpose of this study was to evaluate the clinical results of diverse vascular lesions after treatment with an IPL source. METHOD: Forty Asian patients with vascular lesions were enlisted. The IPL treatment was administered to patients in 4-week sessions. Irradiation wavelength was controlled using cutoff filters ranging from 555 to 950 nm, with a fluence of 15-16J/cm2 (except forehead and zygomatic arch area), with single pulse illumination and a pulse width of 7 msec. RESULTS: At the end of the study, three physicians assessed the results and concluded that 72.5 % of the patients showed excellent or good results from the treatment. However, no difference was observed in 62.5 % of the patients after treatments. Furthermore, no specific adverse effects, except two cases of purpura and crust, were observed after the treatment. CONCLUSION: The treatment of vascular lesions on Asian skin using IPL is an effective, safe, and rapid treatment, with relatively few side effects and high patient satisfaction.
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Humans , Asian People , Forehead , Hair , Lighting , Patient Satisfaction , Purpura , Skin , ZygomaABSTRACT
The present study was undertaken to confirm whether melittin, a major constituent of whole bee venom (WBV), had the ability to produce the same nociceptive responses as those induced by WBV. In the behavioral experiment, changes in mechanical threshold, flinching behaviors and paw thickness (edema) were measured after intraplantar (i.pl.) injection of WBV (0.1 mg & 0.3 mg/paw) and melittin (0.05 mg & 0.15 mg/paw), and intrathecal (i.t.) injection of melittin (6microgram). Also studied were the effects of i.p. (2 mg & 4 mg/kg), i.t. (0.2microgram & 0.4microgram) or i.pl. (0.3 mg) administration of morphine on melittin- induced pain responses. I.pl. injection of melittin at half the dosage of WBV strongly reduced mechanical threshold, and increased flinchings and paw thickness to a similar extent as those induced by WBV. Melittin- and WBV-induced flinchings and changes in mechanical threshold were dose- dependent and had a rapid onset. Paw thickness increased maximally about 1 hr after melittin and WBV treatment. Time-courses of nociceptive responses induced by melittin and WBV were very similar. Melittin-induced decreases in mechanical threshold and flinchings were suppressed by i.p., i.t. or i.pl. injection of morphine. I.t. administration of melittin (6microgram) reduced mechanical threshold of peripheral receptive field and induced flinching behaviors, but did not cause any increase in paw thickness. In the electrophysiological study, i.pl. injection of melittin increased discharge rates of dorsal horn neurons only with C fiber inputs from the peripheral receptive field, which were almost completely blocked by topical application of lidocaine to the sciatic nerve. These findings suggest that pain behaviors induced by WBV are mediated by melittin-induced activation of C afferent fiber, that the melittin- induced pain model is a very useful model for the study of pain, and that melittin-induced nociceptive responses are sensitive to the widely used analgesics, morphine.