RESUMO
Cutaneous Malassezia is an exacerbating factor in patients with atopic dermatitis. We analysed the Malassezia microbiota of adult patients with head and neck atopic dermatitis of different severities (mild, moderate and severe). Of the nine human-associated Malassezia species, the number detected was similar (3.5-4.2 species per case) among the members of all severity groups. However, the ratio of the two major Malassezia species, M. globosa and M. restricta, was different in the severe group.
Assuntos
Dermatite Atópica/complicações , Dermatite Atópica/microbiologia , Dermatomicoses/complicações , Dermatomicoses/microbiologia , Malassezia/classificação , Malassezia/genética , Adulto , Feminino , Humanos , Malassezia/isolamento & purificação , Malassezia/patogenicidade , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Índice de Gravidade de Doença , Pele/microbiologiaRESUMO
Peripherally secreted arginine vasopressin (AVP) plays a role in controlling body fluid homeostasis, and central endogenous AVP acts as a neurotransmitter or neuromodulator. The limbic system, which appears to exert an inhibitory effect on the endocrine hypothalamus, is also innervated by fibres that contain AVP. We examined whether central endogenous AVP is also involved in the control of body fluid homeostasis. To explore this possibility, we examined neuronal activity in the paraventricular nucleus of the hypothalamus (PVN), periventricular parts of the PVN and limbic brain areas, as well as AVP mRNA expression in the PVN and the peripheral secretion of AVP after central salt-loading in rats that had been pretreated i.c.v. with the AVP V(1) receptor antagonist OPC-21268. Neuronal activity in the PVN evaluated in terms of Fos-like immunoreactivity (FLI), especially in the parvocellular subdivisions, was suppressed. On the other hand, FLI was enhanced in the lateral septum, the bed nucleus of the stria terminalis and the anterior hypothalamic area. Similarly, AVP mRNA expression was enhanced in the magnocellular subnucleus of the PVN, despite the lack of a significant difference in the peripheral AVP level between OPC-21268- and vehicle-pretreated groups. We recorded renal sympathetic nerve activity (RSNA) as sympathetic nerve outflow during central salt-loading. The suppression of RSNA was significantly attenuated by i.c.v. pretreatment with OPC-21268. These results suggest that the suppression of RSNA during central salt-loading might be the result of a decrease in neuronal activity in the parvocellular subdivisions of the PVN via the inhibitory action of central endogenous AVP. The parvocellular and magnocellular neurones in the PVN might show different responses to central salt-loading to maintain body fluid homeostasis as a result of the modulatory role of central endogenous AVP.
Assuntos
Arginina Vasopressina/biossíntese , Líquidos Corporais , Homeostase , Neurônios/fisiologia , Núcleo Hipotalâmico Paraventricular/citologia , Cloreto de Sódio/administração & dosagem , Animais , Antagonistas dos Receptores de Hormônios Antidiuréticos , Arginina Vasopressina/genética , Arginina Vasopressina/fisiologia , Pressão Sanguínea , Frequência Cardíaca , Hibridização In Situ , Injeções Intraventriculares , Masculino , RNA Mensageiro/genética , Ratos , Ratos Sprague-DawleyRESUMO
We assessed the safety and efficacy of pulse therapy with terbinafine tablets in 55 patients with dermatophytic onychomycosis. One pulse consisted of oral terbinafine tablets (500 mg day(-1)) given for 1 week usually followed by a 3-week interval. This regimen was repeated twice. Topical 1% terbinafine cream was applied daily. Efficacy was assessed based on both clinical and mycological examinations 1 year after treatment initiation. We observed a complete cure in 41 patients (74.5%), marked improved in three patients (5.6%), slight improvement in three patients (5.6%) and drop out in six patients (10.7%). Two patients (3.6%) discontinued terbinafine because of gastrointestinal disturbance (one patient) and drug-induced eruption (one patient). No patient had abnormal laboratory findings, including liver function tests. In summary, a regimen of three pulses of terbinafine therapy given daily for 1 week in combination with topical application of terbinafine cream appears to be safe and effective in treating dermatophytic onychomycosis and offers advantages in convenience and cost-effectiveness compared with continuous dosing.
Assuntos
Antifúngicos/administração & dosagem , Antifúngicos/efeitos adversos , Naftalenos/administração & dosagem , Naftalenos/efeitos adversos , Onicomicose/tratamento farmacológico , Administração Oral , Administração Tópica , Adulto , Idoso , Arthrodermataceae/efeitos dos fármacos , Feminino , Humanos , Fígado/efeitos dos fármacos , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , Terbinafina , Resultado do TratamentoRESUMO
BACKGROUND: Malassezia species are suspected to be involved in the development of skin lesions in atopic dermatitis (AD) when the response of adult AD to anti-inflammatory treatments is poor. However, a comparative analysis of Malassezia flora between adults and children with AD has not been performed. OBJECTIVES: To compare the cutaneous Malassezia flora between adults and children with AD. METHODS: Scale samples were collected from skin lesions of 58 patients with AD in the head and neck regions (28 males and 30 females; 31 children and 27 adults), and fungal DNA was extracted from the samples directly. The number and identities of the Malassezia species were analysed with high accuracy using a polymerase chain reaction-based culture-independent method. The in vivo level of anti-Malassezia IgE antibody was also assayed. RESULTS: Malassezia restricta was the predominant species in the children with AD, while both M. restricta and M. globosa predominated in the adults. The adults showed increased sensitization in terms of anti-Malassezia-specific IgE responses in the sera to both M. globosa and M. restricta in comparison with the children. CONCLUSIONS: The cutaneous Malassezia flora differs significantly between the two age groups.
Assuntos
Dermatite Atópica/microbiologia , Dermatomicoses/microbiologia , Malassezia/isolamento & purificação , Pele/microbiologia , Adolescente , Adulto , Fatores Etários , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: It has been suggested that Malassezia is associated with the development of skin lesions in psoriasis because of the response of the scalp lesions in psoriasis to antifungal agents. Malassezia restricta and M. globosa are the two major members of the cutaneous Malassezia flora in patients with psoriasis, although they have not been analysed quantitatively. OBJECTIVES: This study quantified the two major cutaneous Malassezia species in psoriatic scale from different body sites using a real-time polymerase chain reaction (PCR) assay. METHODS: Scale samples were collected from lesional and nonlesional skin of 20 Japanese patients with psoriasis and fungal DNA was extracted from the samples directly. All the Malassezia species, including the two major species M. globosa and M. restricta, were quantified with high accuracy, using a real-time PCR assay. RESULTS: Colonization by M. restricta was approximately five times higher at all body sites than colonization by M. globosa. Malassezia colonization was significantly lower in patients with hyperlipidaemia than in patients with normolipidaemia. CONCLUSIONS: Malassezia restricta is the predominant species in psoriatic scale.
Assuntos
Malassezia/isolamento & purificação , Psoríase/microbiologia , Adulto , Idoso , DNA Fúngico/análise , Feminino , Humanos , Hiperlipidemias/complicações , Hiperlipidemias/microbiologia , Malassezia/classificação , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Psoríase/complicações , Psoríase/patologia , Índice de Gravidade de Doença , Pele/microbiologiaRESUMO
Gardenia yellow powders A, B and C, containing geniposide at 0.284%, 0.938% and 2.783%, respectively, were administered orally to male and female SD rats as 3% feed admixtures for 13-weeks to evaluate any potential toxicity. Mean geniposide intake values were 5.72, 18.9 and 56.3mg/kg/day in groups receiving these feed admixtures, respectively. All animals survived the duration of the study. The following findings were evident in the gardenia yellow C group: chromatouria, slightly increased plasma total bilirubin, blackish brown discoloration of the kidneys and liver, brown pigments in the proximal tubular epithelium of the kidneys. Slightly increased plasma total bilirubin was considered to be due to interference of metabolite of geniposide with the system of measurement and not to be a toxic effect since there were no related changes in histopathology of the liver or in any blood chemistry parameters. Other findings were limited to pigmentations or discolorations attributable to metabolites of geniposide. No treatment-related effects were evident on body weight, food consumption, ophthalmology, hematology or organ weights in any group. Therefore, it was concluded that 3-month ingestion of the gardenia yellow powder containing geniposide at 2.783% (approximately 60 mg/kg/day as geniposide intake) does not cause any severe toxic effects.
Assuntos
Corantes de Alimentos/toxicidade , Gardenia/toxicidade , Iridoides/toxicidade , Extratos Vegetais/toxicidade , Piranos/toxicidade , Administração Oral , Animais , Análise Química do Sangue , Peso Corporal/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Histocitoquímica , Masculino , Ratos , Ratos Sprague-Dawley , Estatísticas não Paramétricas , Análise de SobrevidaRESUMO
Tinea capitis caused by Trichophyton tonsurans is currently an epidemic in the United States, Europe, and Japan, and the cultivation of this microorganism is necessary for a definitive diagnosis. We recently developed a real-time PCR TaqMan assay as a culture-independent method for the rapid detection of T. tonsurans from hairbrushes.
Assuntos
Reação em Cadeia da Polimerase/métodos , Tinha do Couro Cabeludo/microbiologia , Trichophyton/isolamento & purificação , Humanos , Taq Polimerase/metabolismo , Tinha do Couro Cabeludo/diagnóstico , Tinha do Couro Cabeludo/epidemiologia , Trichophyton/classificação , Trichophyton/crescimento & desenvolvimentoRESUMO
We report a case of chromomycosis caused by Fonsecaea pedrosoi that developed in the left buttock of a 63-year-old female farmer. About 4 years ago, the patient developed erythema in the left buttock, which gradually spread. At the first consultation, we noted a well-defined, red-brown, infiltrated erythematous plaque (8 x 6 cm). Histopathological examination revealed a granulomatous lesion, containing sclerotic cells, associated with giant cells in the upper dermis. The causative fungus was difficult to identify due to low conidiogenesis, but was eventually identified by slide culture as F. pedrosoi. Excision and skin graft were performed, and no recurrence has been observed after 2 years. In Japan, 212 cases of dematiaceous fungal infection were reported in the period from 1982 to 2001. The causative fungus was F. pedrosoi in the majority of cases (126/212; 66%), followed by Exophiala jeanselmei (36/212; 19%). Similar incidence of dematiaceous fungal infection was reported in male and female patients. The upper limbs were affected most frequently in both male and female patients. Ten cases were associated with visceral lesions.
Assuntos
Ascomicetos/isolamento & purificação , Cromoblastomicose/microbiologia , Cromoblastomicose/patologia , Nádegas/microbiologia , Cromoblastomicose/cirurgia , Exophiala , Feminino , Humanos , Japão , Pessoa de Meia-Idade , Pele/patologiaRESUMO
BACKGROUND: Terbinafine, based on its pharmacokinetic properties, is a good candidate for pulse therapy. There are, as yet, no current guidelines for a terbinafine 1-week pulse regimine. OBJECTIVE: To determine the optimal 1-week pulse dosing regimen for combination therapy of oral terbinafine with complementary 1% terbinafine cream for the treatment of onychomycosis. DESIGN: A total of 69 onychomycosis patients received 250 mg terbinafine, given orally once daily for 7 days as 1-week pulses, separated by intervals of 2-3 weeks, until the desired improvement was observed. A daily application of 1% terbinafine cream was advised through to the evaluation date at 12 months follow-up. The treatment regimens were compared based on the number of pulses and the duration of treatment. RESULTS: The 45 patients (65.2%) who achieved complete cure received an average of 7.8+/-3.5 pulse treatments over 4.8+/-2.6 months. The optimal terbinafine dosing regimen consisted of alternate 1-week pulses, with most patients on this regimen (19/20 cases; 95%) achieving total cure. CONCLUSION: Favorable treatment outcome was gained from this terbinafine 1-week pulse regimen and also better compliance compared with a standard daily regimen.
Assuntos
Antifúngicos/administração & dosagem , Naftalenos/administração & dosagem , Onicomicose/tratamento farmacológico , Administração Oral , Administração Tópica , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , TerbinafinaRESUMO
The present study was designed to determine the lowest dose of orally administered itraconazole and the shortest duration of therapy necessary for treatment of tinea corporis and tinea cruris. For all patients, the itraconazole dose was 100 mg twice a day immediately after meals. Twenty-eight patients received itraconazole on days 1 and 8, 12 patients received itraconazole on days 1 and 2, and five patients received itraconazole only on day 1. Clinical and mycological evaluations were performed at baseline and on day 14. Based on the clinical and mycological responses, treatment efficacy was classified as excellent, good, fair, or poor. "Excellent" and "good" responses made up 86% of the first group, 100% of the second group, and 20% of the third group. A comparison of efficacy ratings of the three regimens showed that the patients who received a single 200-mg dose had a significantly inferior outcome compared with the other two groups. We conclude that an abbreviated oral regimen of itraconazole for treatment of tinea corporis and tinea cruris requires a total dose of at least 400 mg to induce a favorable outcome.
Assuntos
Antifúngicos/uso terapêutico , Itraconazol/uso terapêutico , Microsporum/isolamento & purificação , Tinha/tratamento farmacológico , Trichophyton/isolamento & purificação , Administração Oral , Adolescente , Adulto , Idoso , Antifúngicos/administração & dosagem , Criança , Esquema de Medicação , Feminino , Humanos , Itraconazol/administração & dosagem , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Tinha/microbiologia , Resultado do TratamentoRESUMO
An epidemiological investigation was conducted to determine the prevalence and circumstances of untreated, unsuspected tinea pedis and tinea unguium, morbid conditions that could be termed occult athlete's foot, in patients visiting a dermatology clinic in Tokyo, Japan, for the first time, for other complaints. All subjects completed a questionnaire covering comprehensive anamnestic details, and were examined for disposition of toes, presence of signs suggestive of tinea pedis, other diseases of the foot, score of clinical signs and symptoms, potassium hydroxide (KOH) test, severity score, and mycological culture. The results showed that the prevalence of occult athlete's foot was 25%, and that 59% of those cases were complicated by tinea unguium. The characteristics of patients with occult athlete's foot included a higher proportion of men and a tendency toward a low clinical score together with a high severity score. In the patient background, a strong correlation was observed between a positive KOH test result and characteristics such as age, disposition of toes, and predisposing disease.
Assuntos
Dermatoses do Pé , Onicomicose , Tinha dos Pés , Adolescente , Adulto , Idoso , Feminino , Dermatoses do Pé/epidemiologia , Dermatoses do Pé/microbiologia , Dermatoses do Pé/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Onicomicose/epidemiologia , Onicomicose/microbiologia , Onicomicose/fisiopatologia , Prevalência , Fatores de Risco , Índice de Gravidade de Doença , Inquéritos e Questionários , Tinha dos Pés/epidemiologia , Tinha dos Pés/microbiologia , Tinha dos Pés/fisiopatologia , Tóquio/epidemiologia , Trichophyton/classificação , Trichophyton/isolamento & purificaçãoRESUMO
We report a case of subcutaneous phaeohyphomycosis by Exophiala jeanselmei that appeared on the extensor surface of the left lower leg of a 34-year-old woman with systemic lupus erythematosus (SLE). The superficial symptoms were a subcutaneous nodule 2.5 x 2 cm in size discharging a serous exudate from its center. Histopathological examination revealed granulomatous changes including large numbers of neutrophils in the dermis and the subcutaneous tissues. In addition, periodic acid-Schiff-positive fungal elements consisting of many yeast-like cells and chains of cells with hyphae were seen. The statistics on E. jeanselmei infections in Japan indicated that 54 cases (24 in men and 30 in women) had been reported, of which 50 (21 in men and 29 in women) were phaeohyphomycosis, and about half had underlying diseases; and the sites of the lesions were mainly on the extremities.
Assuntos
Dermatomicoses/diagnóstico , Dermatomicoses/microbiologia , Exophiala/isolamento & purificação , Lúpus Eritematoso Sistêmico/complicações , Adulto , Dermatomicoses/cirurgia , Feminino , HumanosRESUMO
In this study, we investigated epidemiological and clinical aspects of dermatophyte foot infections among employees of one dairy product company located in Kanagawa prefecture in central Japan. Sixty-nine of 377 subjects were reported having "athlete's foot" in response to a simple questionnaire. A subsequent mycological examination revealed 41 untreated patients with tinea pedis and/or tinea unguium (89% of subjects examined) and the overall prevalence was estimated at 18%. Comparing severity scores of five clinical symptoms (itching, erythema, vesicles/pustules, erosion/maceration, and scales) between those untreated patients within the subjects and another group of patients who spontaneously attended dermatological clinics to treat tinea pedis, itching, erythema, and total score were significantly higher in the latter group.
Assuntos
Tinha dos Pés/epidemiologia , Tinha dos Pés/patologia , Trichophyton , Adulto , Eritema/patologia , Feminino , Humanos , Japão/epidemiologia , Masculino , Programas de Rastreamento , Prevalência , Prurido/patologia , Psoríase/patologia , Índice de Gravidade de Doença , Inquéritos e Questionários , Tinha dos Pés/microbiologia , Trichophyton/isolamento & purificaçãoRESUMO
The second case of phaeohyphomycosis caused by Veronaea botryosa in China, in a 12-year-old boy from Jiangsu Province, is presented. Based on direct examination of the scrapings from crusted lesions; histologic examination of the biopsy tissue showing septate, phaeoid hyphal elements; and the culture exhibiting sympodial, conidiogenous cells producing predominantly two-celled, cylindric conidia, the etiologic agent was identified as V. botryosa.
Assuntos
Dermatomicoses/etiologia , Fungos Mitospóricos/patogenicidade , Criança , China , Dermatomicoses/diagnóstico , Dermatomicoses/tratamento farmacológico , Dermatomicoses/microbiologia , Humanos , Masculino , Fungos Mitospóricos/isolamento & purificação , Microbiologia do Solo , Tela Subcutânea/microbiologia , Tela Subcutânea/patologiaRESUMO
A case of multiple subcutaneous nocardial abscesses is reported in a patient who received systemic corticosteroids over a period of about 4 years for the treatment of visceral sarcoidosis. The diagnosis of subcutaneous abscess caused by Nocardia asteroides was made based on bacteriological examination. It could not be determined before treatment whether the abscesses represented primary or secondary nocardiosis. Surgical drainage and systemic administration of minocycline hydrochloride dramatically resolved the cutaneous lesions. To the authors' knowledge, this is the first reported case in Japan of primary cutaneous nocardiosis in a patient with sarcoidosis.
Assuntos
Abscesso/diagnóstico , Nocardiose/diagnóstico , Nocardia asteroides , Sarcoidose/complicações , Dermatopatias Infecciosas/diagnóstico , Abscesso/etiologia , Abscesso/terapia , Feminino , Humanos , Pessoa de Meia-Idade , Nocardiose/etiologia , Nocardiose/terapia , Dermatopatias Infecciosas/etiologia , Dermatopatias Infecciosas/terapiaRESUMO
A 69-year-old man, a carpenter with idiopathic thrombopenic purpura and interstitial pneumonia, was treated with steroid pulse therapy and antibiotics. On the seventh day of steroid therapy, a conglomeration of papules, vesicles and pustules appeared in an area of the left buttock in contact with his napkin. In a Parker KOH specimen of the crust of the lesion, many non-septate hyphae were seen, and culture of material obtained by biopsy yielded Rhizopus microsporus var. microsporus. Ketoconazole cream was applied topically for 1 week, and the exanthema healed. After the third month of inpatient treatment, the patient's overall condition had returned to normal, and he was discharged. Cutaneous zygomycosis is a rare disease, and only 19 cases have been reported in Japan. Its characteristics, as reported in these cases, have been collected and collated.
Assuntos
Dermatomicoses/patologia , Mucormicose/patologia , Idoso , Dermatomicoses/tratamento farmacológico , Dermatomicoses/etiologia , Fungos , Humanos , Japão , Masculino , Mucormicose/tratamento farmacológico , Mucormicose/etiologia , Rhizopus/isolamento & purificaçãoRESUMO
From among 428 Nepalese schoolchildren hair samples of 102 children with clinical features of tinea capitis, obtained by the sterile hairbrush method, were examined by mycological techniques. Age varied between 4-16 years. Itching was experienced by 96.1% sample subjects and hair loss by 32.4%. Of the 102, 11 (10.8%) were positive for Trichophyton violaceum (TV), 6 being from urban areas, the rest from rural areas. Amongst the 11 patients, 7 (63.6%) were girls and rest boys. Statistical associations were observed between the place of haircut and isolation of the organism (chi2 = 15.2, p <0.01). Statistical association was also present between frequency of bathing and isolation of organism. Sharing of combs was associated with the culture-positive subjects. The prevalence of tinea capitis in the urban and rural children was 2.3% and 3.0%, respectively. The only isolated organism was TV. An association of the isolation of TV was found with risk factors such as family members, sharing of combs, frequency of bathing with the organism. Hair loss was more common in the urban children. Discouragement of sharing combs, increased frequency of hair washing, and use of uncontaminated hair cutting instruments are recommended.
Assuntos
Tinha do Couro Cabeludo/epidemiologia , Tinha do Couro Cabeludo/microbiologia , Adolescente , Distribuição de Qui-Quadrado , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Nepal/epidemiologia , Fatores de Risco , Trichophyton/isolamento & purificaçãoRESUMO
We investigated background factors of patients that affect the response of onycomycosis to pulse therapy with itraconazole. The regimen used in this study involved administering 200 mg of itraconazole orally on a daily basis for 1 week as one pulse, which is half of the normally recommended dose. The number of pulses was fixed at one per month, and altered in accordance with improvements in the infected nails and/or the patients' request. Patient background (n = 63) including sex, age, occupation, duration of the disease, site of lesion (fingernail, toenail), number of affected nails, clinical types, severity of thickening, presence or absence of pathogens, the presence or absence of underlying diseases such as adult onset diseases, turbidity of the target nails before therapy and the number and duration of pulses was investigated. The efficacy of the therapy was evaluated after 12 months. A complete cure was judged to have taken place if an entirely healthy nail plate re-grew in place of the diseased nail, whereas lack of success was defined as the persistence of lesions beyond the designated time period. The average number and duration of pulses were 4.7 +/- 3.2 times over 5.6 +/- 4.3 months, respectively. The rate of complete cure was 62%. Factors in the patients' background that were judged to have an influence on treatment results were the relative duration of the disease, the number of affected nails, and severity of thickening. With regard to the efficacy of the therapy in terms of the number and duration of pulses, 78% of 23 patients who were given pulse therapy two to six times during a course of 2 to 6 months achieved total cure.
Assuntos
Antifúngicos/uso terapêutico , Itraconazol/uso terapêutico , Onicomicose/tratamento farmacológico , Administração Oral , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antifúngicos/administração & dosagem , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Itraconazol/administração & dosagem , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Ocupações , Onicomicose/patologia , Pulsoterapia , Fatores de Tempo , Resultado do TratamentoRESUMO
OBJECTIVE: To investigate the effects of a selective inhibitor of neuronal nitric oxide synthase (nNOS), 7-nitroindazole, on peripheral sympathetic outflow in Dahl rats. DESIGN AND METHODS: Dahl salt-sensitive and salt-resistant rats were fed either a regular-salt (0.4% NaCl) or a high-salt (8% NaCl) diet for 4 weeks. In chronically instrumented conscious rats, renal sympathetic nerve activity (RSNA) was measured in both baroreceptor-loaded and baroreceptor-unloaded states. The baroreceptor unload was performed by decreasing arterial pressure with occlusion of the inferior vena cava. RESULTS: 7-Nitroindazole (307 micromol/kg intraperitoneally) increased resting RSNA from 24 +/- 3% to 38 +/- 6% with an increase in mean arterial pressure of 15 +/- 3 mmHg, and increased baroreceptor-unloaded RSNA from 100% to 278 +/- 16% in salt-sensitive Dahl rats receiving a high-salt diet However, 7-nitroindazole did not increase resting RSNA, but did increase baroreceptor-unloaded RSNA from 100% to 179 +/- 15%, 177 +/- 15%, and 133 +/- 4% in salt-sensitive Dahl rats receiving a regular-salt diet, salt-resistant Dahl rats receiving a high-salt diet, and salt-resistant Dahl rats receiving a regular-salt diet, respectively. The high-salt diet significantly increased the baroreceptor-unloaded RSNA more than the regular-salt diet did, in both salt-sensitive and salt-resistant rats. After administration of the vehicle for 7-nitroindazole (peanut oil), L-arginine (100 micromol/kg per min for 10 min) decreased both resting and baroreceptor-unloaded RSNA, whereas after pretreatment with 7-nitroindazole, the L-arginine-induced suppression was reversed, in Dahl salt-sensitive rats receiving a high-salt diet. CONCLUSIONS: Neuronal nitric oxide may suppress the sympathetic discharge generated before baroreflex-mediated inhibition in all rats. This neuronal nitric oxide-mediated suppression was enhanced by the salt load in both salt-resistant and salt-sensitive Dahl rats. Finally, the neuronal nitric oxide-mediated suppression in tonic peripheral sympathetic outflow may be greatly enhanced in salt-sensitive hypertension.