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1.
Clin Cancer Res ; 25(11): 3205-3209, 2019 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-30692099

RESUMEN

The FDA approved ivosidenib (Tibsovo; Agios), a small-molecule inhibitor of isocitrate dehydrogenase (IDH)1 on July 20, 2018, for treatment of adults with relapsed or refractory acute myeloid leukemia (R/R AML) with susceptible IDH1 mutation as detected by an FDA-approved test. The efficacy of ivosidenib was established on the basis of complete remission (CR) + CR with partial hematologic recovery (CRh) rate, duration of CR + CRh, and conversion from transfusion dependence (TD) to transfusion independence (TI) in Study AG120-C-001, a single-arm trial. With median follow-up of 8.3 months for 174 adults with IDH1-mutated R/R AML treated with 500 mg ivosidenib daily, the CR + CRh rate was 33% [95% confidence interval (CI), 26-40], median duration of response was 8.2 (95% CI, 5.6-12) months, and conversion from TD to TI occurred in 37% of patients. These endpoints reflect short-term benefit in patients with an unmet medical need; long-term efficacy outcomes were not assessed. Serious adverse reactions (AR) in ≥5% of patients were differentiation syndrome (10%), leukocytosis (10%), and QT interval prolongation (7%). Common (≥20%) ARs of any grade were fatigue, leukocytosis, arthralgia, diarrhea, dyspnea, edema, nausea, mucositis, QT interval prolongation, rash, pyrexia, cough, and constipation. Assessment of long-term safety of ivosidenib is a condition of this approval.


Asunto(s)
Antineoplásicos/uso terapéutico , Aprobación de Drogas , Glicina/análogos & derivados , Isocitrato Deshidrogenasa/antagonistas & inhibidores , Isocitrato Deshidrogenasa/genética , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Mutación , Piridinas/uso terapéutico , Antineoplásicos/farmacología , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Glicina/farmacología , Glicina/uso terapéutico , Humanos , Piridinas/farmacología , Resultado del Tratamiento , Estados Unidos , United States Food and Drug Administration
2.
Harmful Algae ; 60: 70-80, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-28073564

RESUMEN

While numerous strategies have been used to educate and notify the public about potential hazards from exposure to Harmful Algal Blooms (HABs), at present there are no national guidelines or suggested outreach approaches. To raise public awareness and determine effective HAB outreach methods, two Washington State agencies and three counties in the Puget Sound region implemented several education and notification strategies. These approaches were rated for effectiveness by state and county public health and water quality professionals. At the state level, the most effective action was a three-tiered advisory posting protocol for notifying external users that was introduced to local health jurisdictions at workshops around the state. Supplemental permanent signage is recommended for lakes with blooms to overcome the time lag between HAB onset and testing/posting. The state also implements effective notification of toxicity test results through a web-based HAB database and listserv. Lake residents were best notified through electronic alerts including email and social media while mailers to lake residents were useful during initial HAB events and to gain subscribers to electronic alerts. Press releases were most valuable when used sparingly for severe blooms or for blooms in large lakes. Initial analyses of lake recreational use indicates these strategies encourage behavior change in lake users. Based on these findings, a general framework for HAB outreach and a specific notification strategy is proposed to assist other regions or agencies that are developing HAB education and notification programs.


Asunto(s)
Monitoreo del Ambiente , Floraciones de Algas Nocivas , Salud Pública/educación , Salud Pública/métodos , Lagos/parasitología , Washingtón , Calidad del Agua
3.
Clin Cancer Res ; 16(20): 4921-7, 2010 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-20739433

RESUMEN

PURPOSE: On September 24, 2009, the U.S. Food and Drug Administration granted accelerated approval for Folotyn (pralatrexate injection, Allos Therapeutics, Inc.) as a single agent for the treatment of patients with relapsed or refractory peripheral T-cell lymphoma (PTCL); it is the first drug approved for this indication. EXPERIMENTAL DESIGN: This review was based on study PDX-008, a phase II, single-arm, nonrandomized, open-label, international, multicenter trial, designed to evaluate the safety and efficacy of pralatrexate when administered concurrently with vitamin B(12) and folic acid supplementation in patients with relapsed or refractory PTCL. RESULTS: The overall response rate was 27% in 109 evaluable patients [95% confidence interval (CI), 19-36%]. Twelve percent of 109 evaluable patients (95% CI, 7-20%)] had a response duration of ≥14 weeks. Six of these 13 patients achieved a complete response, and one patient had complete response unconfirmed. The most common grade 3 and 4 toxicities were thrombocytopenia, mucositis, and neutropenia. CONCLUSION: This accelerated approval was based on a response rate that is reasonably likely to predict clinical benefit in this heavily pretreated patient population with this rare disease. The applicant has committed to conducting postmarketing clinical trials to assess clinical benefit. The recommended starting dose of pralatrexate in patients with relapsed or refractory PTCL is 30 mg/m(2) via intravenous push over 3 to 5 min weekly for 6 weeks followed by a one-week rest (one cycle). Intramuscular injection of 1 mg vitamin B(12) should be administered every 8 to 10 weeks along with 1.0 mg folic acid given orally once a day.


Asunto(s)
Aminopterina/análogos & derivados , Linfoma de Células T/tratamiento farmacológico , Anciano , Aminopterina/efectos adversos , Aminopterina/química , Aminopterina/uso terapéutico , Aprobación de Drogas , Femenino , Antagonistas del Ácido Fólico/efectos adversos , Antagonistas del Ácido Fólico/química , Antagonistas del Ácido Fólico/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Estados Unidos , United States Food and Drug Administration
4.
Oncologist ; 13(10): 1120-7, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18922829

RESUMEN

PURPOSE: Lenalidomide (CC-5013, Revlimid; Celgene Corporation, Summit, NJ), a thalidomide analogue, was granted approval by the U.S. Food and Drug Administration (FDA) on June 29, 2006, for use in combination with dexamethasone in patients with multiple myeloma (MM) who have received at least one prior therapy. The FDA approved lenalidomide with a restricted distribution program, RevAssist. EXPERIMENTAL DESIGN: In two randomized, double-blind, multicenter studies, the combination of lenalidomide and dexamethasone (LD) was compared with placebo and dexamethasone (PD) in patients with MM who had received at least one prior therapy. The primary endpoint was time to progression (TTP). RESULTS: Following a prespecified interim analysis of TTP, an independent data-monitoring committee advised the sponsor to halt the two studies. For both studies, the interim analysis for efficacy revealed a statistically significant longer TTP with LD than with PD. The most clinically relevant grade 3 and 4 adverse events that occurred more frequently in the LD arm were neutropenia, thrombocytopenia, deep vein thrombosis, pulmonary embolism, and atrial fibrillation. Thrombotic or thromboembolic events, including deep vein thrombosis, pulmonary embolism, thrombosis, and intracranial venous sinus thrombosis were reported more frequently in patients treated with LD than with PD. CONCLUSIONS: The FDA approved lenalidomide based on interim results from two multicenter, placebo-controlled, randomized trials comparing the combination of LD with PD that revealed a longer TTP with LD than with PD. The major toxicity observed during these trials was myelosuppression. The serious toxicities included thromboembolic events. Lenalidomide is only available under the RevAssist Program.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Dexametasona/uso terapéutico , Mieloma Múltiple/tratamiento farmacológico , Anciano , Anciano de 80 o más Años , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Dexametasona/administración & dosificación , Dexametasona/efectos adversos , Progresión de la Enfermedad , Método Doble Ciego , Aprobación de Drogas , Femenino , Humanos , Lenalidomida , Masculino , Persona de Mediana Edad , Placebos , Talidomida/administración & dosificación , Talidomida/efectos adversos , Talidomida/análogos & derivados , Estados Unidos , United States Food and Drug Administration
5.
Clin Cancer Res ; 12(24): 7271-8, 2006 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-17189398

RESUMEN

PURPOSE: This report describes the U.S. Food and Drug Administration (FDA) review and approval of sorafenib (Nexavar, BAY43-9006), a new small-molecule, oral, multi-kinase inhibitor for the treatment of patients with advanced renal cell carcinoma (RCC). EXPERIMENTAL DESIGN: After meeting with sponsors during development studies of sorafenib, the FDA reviewed the phase 3 protocol under the Special Protocol Assessment mechanism. Following new drug application submission, FDA independently analyzed the results of two studies in advanced RCC: a large, randomized, double-blinded, phase 3 international trial of single-agent sorafenib and a supportive phase 2 study. RESULTS: In the phase 3 trial, 902 patients with advanced progressive RCC after one prior systemic therapy were randomized to 400 mg sorafenib twice daily plus best supportive care or to a matching placebo plus best supportive care. Primary study end points included overall survival and progression-free survival (PFS). A PFS analysis, pre-specified and conducted after a total of 342 events, showed statistically significant superiority for the sorafenib group (median = 167 days) compared with that for the controls (median = 84 days, log-rank P < 0.000001); the sorafenib/placebo hazard ratio was 0.44 (95% confidence interval, 0.35-0.55). Results were similar regardless of patient risk score, performance status, age, or prior therapy. The (partial) response rate to sorafenib was 2.1%. Overall survival results are preliminary. The principal toxicities in the sorafenib patients included reversible skin rashes in 40% and hand-foot skin reaction in 30%; diarrhea was reported in 43%, treatment-emergent hypertension was reported in 17%, and sensory neuropathic changes were reported in 13%. Grade 4 adverse events were uncommon. Grade 3 adverse events were hand-foot skin reaction (6%), fatigue (5%), and hypertension (3%). Laboratory findings included asymptomatic hypophosphatemia in 45% of sorafenib patients versus 11% in the placebo arm and elevation of serum lipase in 41% of sorafenib patients versus 30% in the placebo arm. Grade 4 pancreatitis was reported in two sorafenib patients, although both patients subsequently resumed sorafenib, with one at full dose. CONCLUSIONS: Sorafenib received FDA regular approval on December 20, 2005 for the treatment of advanced RCC based on the persuasive magnitude of improvement in PFS with acceptable safety. The recommended dose is 400 mg (two 200-mg tablets) twice daily taken either 1 h before or 2 h after meals. Adverse events were accommodated by temporary dose interruptions or reductions.


Asunto(s)
Bencenosulfonatos/uso terapéutico , Carcinoma de Células Renales/tratamiento farmacológico , Evaluación de Medicamentos , Neoplasias Renales/tratamiento farmacológico , Piridinas/uso terapéutico , Antineoplásicos/efectos adversos , Antineoplásicos/uso terapéutico , Bencenosulfonatos/efectos adversos , Ensayos Clínicos Fase II como Asunto , Ensayos Clínicos Fase III como Asunto , Supervivencia sin Enfermedad , Método Doble Ciego , Humanos , Modelos Biológicos , Niacinamida/análogos & derivados , Compuestos de Fenilurea , Placebos , Piridinas/efectos adversos , Ensayos Clínicos Controlados Aleatorios como Asunto , Sorafenib , Estados Unidos , United States Food and Drug Administration
6.
Clin Cancer Res ; 11(18): 6414-21, 2005 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-16166415

RESUMEN

PURPOSE: To describe the Food and Drug Administration (FDA) review and approval of erlotinib (Tarceva, OSI Pharmaceuticals, Melville, NY) for treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) after failure of at least one prior chemotherapy regimen. EXPERIMENTAL DESIGN: The FDA reviewed raw data in electronic format from a randomized controlled clinical trial comparing erlotinib with placebo in patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen. RESULTS: Patients were randomized in a 2:1 ratio (erlotinib, n = 488 and placebo, n = 243). Erlotinib was superior to placebo for survival, progression-free survival, and tumor response rate. Exploratory analyses indicate that epidermal growth factor receptor status may be an important predictor of the erlotinib survival effect. Rash (75% versus 17%) and diarrhea (54% versus 18%) in the erlotnib and placebo group respectively were the most common adverse events. Severe rash occurred in 9% and severe diarrhea in 6% of erlotinib-treated patients and each resulted in study discontinuation in 1% of patients. Dose reductions were required for 10% of patients with rash and 4% of patients with diarrhea. CONCLUSIONS: On November 18, 2004, the FDA granted erlotinib regular approval for treatment of patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen. The applicant has committed to conduct post-marketing clinical trials to assess further the effect of epidermal growth factor receptor expression, measured with immunohistochemical staining, on erlotinib treatment effect.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Aprobación de Drogas , Neoplasias Pulmonares/tratamiento farmacológico , Quinazolinas/uso terapéutico , Adolescente , Adulto , Carcinoma de Pulmón de Células no Pequeñas/patología , Diarrea/inducido químicamente , Receptores ErbB/antagonistas & inhibidores , Clorhidrato de Erlotinib , Exantema/inducido químicamente , Femenino , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Inhibidores de Proteínas Quinasas/efectos adversos , Inhibidores de Proteínas Quinasas/uso terapéutico , Calidad de Vida , Quinazolinas/efectos adversos , Análisis de Supervivencia , Insuficiencia del Tratamiento , Resultado del Tratamiento , Estados Unidos , United States Food and Drug Administration
8.
Clin Cancer Res ; 9(12): 4309-17, 2003 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-14555500

RESUMEN

PURPOSE: Patients with hormone-sensitive breast cancer who have responded to tamoxifen (TAM) may receive additional benefit from a second endocrine agent after progression or relapse after TAM therapy. Fulvestrant (FVT; Faslodex; i.m. injection, ICI 182,780; AstraZeneca Pharmaceuticals, Wilmington, DE) was developed as a selective antagonist of estrogen. In postmenopausal women, FVT is reported to inhibit the proliferative effects of estrogen on sensitive tissues and has no apparent measurable estrogenic activity. In this report, we describe the data and analyses supporting marketing approval for FVT by the United States Food and Drug Administration (FDA). EXPERIMENTAL DESIGN: The FDA review of 16 clinical trials and 6 pharmacokinetic trials, as well as preclinical pharmacology and chemistry data, are described. The bases for marketing approval are summarized. RESULTS: Toxicology studies in the mouse, rat, and dog showed minimal toxicity except for antiestrogenic effects. Because of FVT aqueous insolubility, an i.m. formulation, given at monthly intervals, was selected for clinical studies. Pharmacokinetic studies demonstrated sustained concentrations with monthly injection. In in vitro studies FVT was extensively metabolized, primarily by hepatic cytochrome P450 3A4. Phase I studies showed minimal toxicity, and the maximal dose (250 mg) was limited by FVT solubility. In two Phase III trials, 851 patients were randomized to either 250 mg FVT i.m. monthly or to anastrozole (ANZ) 1 mg p.o. daily. Ninety-six percent of patients had received TAM previously for early (adjuvant treatment) or advanced breast cancer. Response rates (RR) were 17% for both FVT and ANZ study arms in the North American trial, and were 20% versus 15% for FVT versus ANZ, respectively, in the European trial. There were no observed differences between study arms with respect to time to progression or survival. The most common FVT adverse events reported as potentially treatment-related were injection site reactions and hot flashes. CONCLUSIONS: FVT was approved on April 25, 2002 by the FDA for the treatment of hormone receptor-positive metastatic breast cancer in postmenopausal women with disease progression after antiestrogen therapy. The recommended dose is 250 mg i.m. monthly as a single 5 ml injection or as two concurrent 2.5 ml injections into the buttocks. Approval was based on results of two randomized trials comparing response rates and time to progression of FVT- and ANZ-treated patients. Complete prescribing information is available on the FDA website.


Asunto(s)
Antineoplásicos Hormonales/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Estradiol/análogos & derivados , Estradiol/uso terapéutico , Posmenopausia , Anastrozol , Antineoplásicos Hormonales/efectos adversos , Antineoplásicos Hormonales/farmacología , Neoplasias de la Mama/secundario , Ensayos Clínicos como Asunto , Aprobación de Drogas , Estradiol/efectos adversos , Estradiol/farmacología , Femenino , Fulvestrant , Humanos , Nitrilos/uso terapéutico , Tasa de Supervivencia , Resultado del Tratamiento , Triazoles/uso terapéutico , Estados Unidos , United States Food and Drug Administration
9.
Clin Cancer Res ; 8(10): 3034-8, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12374669

RESUMEN

PURPOSE: Imatinib mesylate (Gleevec; Novartis, East Hanover, NJ)is a receptor tyrosine kinase inhibitor approved previously in 2001 by the United States Food and Drug Administration for the treatment of chronic myelogenous leukemia in blast crisis, accelerated phase, or in chronic phase after failure of IFN-alpha therapy. We review herein the clinical profile of this drug and the regulatory review leading to the approval of a supplemental New Drug Application for the treatment of metastatic and/or unresectable malignant gastrointestinal stromal tumors (GISTs). EXPERIMENTAL DESIGN: We discuss the efficacy and side effects of imatinib mesylate in a Phase II trial of 147 patients with metastatic and/or unresectable malignant GISTs, the basis for marketing approval, and postmarketing commitments by the drug's manufacturer. RESULTS: Imatinib was assessed in a single, open-label trial involving one European center and three centers in the United States. Seventy-three patients were randomly allocated to receive 400 mg of imatinib daily, and 74 patients received 600 mg daily. At the study report cutoff date, an objective response was confirmed in 56 patients; the overall response rate for the combined study arms was 38% (95% confidence interval, 30-46%). These responses were all partial responses. There was no statistically significant difference in response rates between the two dose groups. Adverse events included edema, fluid retention, nausea, vomiting, diarrhea, myalgias, skin rash, bone marrow suppression, bleeding, and elevations in aspartate aminotransferase, alanine aminotransferase, or bilirubin. Bleeding into the gastrointestinal tract or intratumoral sites occurred in 7 patients (5%) and was not correlated with thrombocytopenia or tumor bulk. The pharmacokinetics of imatinib in GIST patients were similar to those of chronic myelogenous leukemia patients. CONCLUSIONS: On February 1, 2001, imatinib mesylate was approved by the United States Food and Drug Administration for the treatment of malignant metastatic and/or unresectable GISTs. The recommended dose is 400 or 600 mg daily.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Antineoplásicos/uso terapéutico , Neoplasias Gastrointestinales/tratamiento farmacológico , Piperazinas/uso terapéutico , Pirimidinas/uso terapéutico , Células del Estroma/patología , Adenocarcinoma/secundario , Adenocarcinoma/cirugía , Adulto , Anciano , Antineoplásicos/efectos adversos , Benzamidas , Aprobación de Drogas , Femenino , Neoplasias Gastrointestinales/patología , Neoplasias Gastrointestinales/cirugía , Humanos , Mesilato de Imatinib , Masculino , Persona de Mediana Edad , Piperazinas/efectos adversos , Proteínas Proto-Oncogénicas c-kit/metabolismo , Pirimidinas/efectos adversos , Inducción de Remisión , Células del Estroma/metabolismo , Distribución Tisular , Resultado del Tratamiento , Estados Unidos , United States Food and Drug Administration
10.
Pain ; 59(2): 287-300, 1994 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7892027

RESUMEN

To address the mechanisms of hyperalgesia and dorsal horn plasticity following peripheral tissue inflammation, the effects of adjuvant-induced inflammation of the rat hindpaw on behavioral nociception and nociceptive neuronal activity in the superficial dorsal horn were examined in neonatally capsaicin-treated rats 6-8 weeks of age. Capsaicin treatment resulted in an 82% loss of unmyelinated fibers in L5 dorsal roots, a dramatic reduction of substance P-like immunoreactivity in the spinal cord, and a significant decrease in the percentage of dorsal horn nociceptive neurons that responded to C-fiber stimulation and noxious heating of the skin. The thermal nociceptive threshold was significantly increased in capsaicin-treated rats, but behavioral hyperalgesia to thermal stimuli still developed in response to inflammation. Following inflammation, there was a significant decrease in mechanical threshold and an increase in response duration to mechanical stimuli in both vehicle- and capsaicin-treated rats, suggesting that a state of mechanical hyperalgesia was also induced. The capsaicin treatment appears to have differential effects on nociceptive specific (NS) and wide-dynamic-range (WDR) neurons in inflamed rats. Expansion of the receptive fields of nociceptive neurons, a measure of the effect of inflammation-induced CNS plasticity, was less extensive for NS than for WDR neurons in capsaicin-treated rats. Compared to vehicle-treated rats, a smaller population of NS neurons, but a similar percentage of WDR neurons, had background activity in inflamed capsaicin-treated rats. C-fiber strength electrical stimulation of the sciatic nerve produced expansion of the receptive fields in a greater portion of NS neurons (53%, P < 0.05) in capsaicin- than in vehicle-treated rats (32%). There was no difference in stimulation-induced expansion of the receptive fields for WDR neurons between vehicle- or capsaicin-treated rats. An N-methyl-D-aspartate receptor antagonist, MK-801, attenuated the behavioral hyperalgesia and reduced the receptive field size of dorsal horn neurons in inflamed capsaicin- and vehicle-treated rats. The data suggest that while capsaicin-sensitive primary afferents may be involved in neuronal plasticity induced by peripheral tissue inflammation, changes in the capsaicin-insensitive WDR and NS populations are sufficient to produce thermal and mechanical hyperalgesia after the loss of capsaicin-sensitive primary afferents.


Asunto(s)
Animales Recién Nacidos/fisiología , Capsaicina , Hiperalgesia/patología , Inflamación/patología , Nociceptores/fisiología , Médula Espinal/fisiología , Animales , Conducta Animal/fisiología , Maleato de Dizocilpina/farmacología , Estimulación Eléctrica , Femenino , Adyuvante de Freund , Hiperalgesia/inducido químicamente , Hiperalgesia/psicología , Inmunohistoquímica , Inflamación/inducido químicamente , Microscopía Electrónica , Fibras Nerviosas/fisiología , Fibras Nerviosas/ultraestructura , Neuronas Aferentes/efectos de los fármacos , Neuronas Aferentes/fisiología , Estimulación Física , Ratas , Ratas Sprague-Dawley , Médula Espinal/patología
11.
Pain ; 55(3): 313-317, 1993 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8121692

RESUMEN

Drug combination studies often examine the possibility of synergy between drugs. Synergy is defined as an effect of a combination of drugs greater than that expected from the effects of the drugs given individually. One technique used by several investigators is the use of analysis of variance (ANOVA) to determine synergy. In this discussion, the argument is made that due to the pharmacology of drug combination studies the conditions necessary to support the use of ANOVA to detect synergy are typically not met. Therefore, the ANOVA technique is invalid for these drug combination studies.


Asunto(s)
Análisis de Varianza , Sinergismo Farmacológico , Relación Dosis-Respuesta a Droga , Cinética , Receptores de Droga/efectos de los fármacos , Proyectos de Investigación
12.
Pain ; 55(1): 63-70, 1993 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7904058

RESUMEN

We examined the ability of the alpha 2-adrenoceptor agonist, ST-91, microinjected into the medullary dorsal horn (MDH), to diminish the sensory-discriminative features of noxious heat stimuli in awake behaving monkeys. Two monkeys performed a noxious thermal detection task and the time to detection of small increases in heat served as a measure of the perceived intensity of pain. ST-91 microinjected into the MDH (1.0, 3.0, 10.0 and 30.0 micrograms/0.4 microliter) produced dose-dependent increases in detection time to graded temperature increases (0.4-1.0 degrees C) from a noxious 46 degrees C base line. These dose-dependent effects were attenuated by the systemic administration of the alpha 2-adrenoceptor antagonist, idazoxan (2.0 mg/kg, i.m.), but not by the alpha 1-adrenoceptor antagonist, prazosin (0.5 mg/kg, i.m.) or the opioid-receptor antagonist, naloxone (0.5 mg/kg, i.m.). The effect of ST-91 on detection latency of thermal stimuli was not the result of alterations in attentional, motivational or motoric aspects of the monkeys' behavior, because detection of visual stimuli and non-noxious temperature coolings (36.0-34.5 degrees C) in a similar paradigm were not consistently altered. Microinjection of morphine (3.0 mg) into the MDH also increased detection latency of the noxious heat stimuli. Systemic administration of the opioid-receptor antagonist, naloxone (0.5 mg/kg), and the alpha 2-adrenoceptor antagonist, idazoxan (2.0 mg/kg, i.m.) attenuated these effects of morphine. In a separate experiment, morphine (5.0 micrograms) microinjected into the MDH induced facial scratching behavior. Idazoxan (2.0 mg/kg) was effective at attenuating this scratching behavior.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Conducta Animal/fisiología , Norepinefrina/fisiología , Dolor/psicología , Receptores Opioides/fisiología , Antagonistas Adrenérgicos , Agonistas alfa-Adrenérgicos/farmacología , Antagonistas Adrenérgicos alfa/farmacología , Animales , Clonidina/análogos & derivados , Clonidina/farmacología , Dioxanos/farmacología , Electrofisiología , Calor , Idazoxan , Macaca fascicularis , Macaca mulatta , Masculino , Bulbo Raquídeo/fisiología , Microinyecciones , Naloxona/farmacología , Estimulación Física
14.
Pain ; 50(3): 331-344, 1992 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1454389

RESUMEN

The involvement of NMDA receptors in rats with peripheral inflammation and hyperalgesia was evaluated by administration of the non-competitive NMDA receptor antagonist, MK-801. Inflammation and hyperalgesia was induced by intradermal injection of complete Freund's adjuvant (CFA) or carrageenan into the left hind paw. The latency of paw withdrawal from a thermal stimulus was used as a measure of hyperalgesia in awake rats. MK-801 (1.6 mg/kg, i.p., or 31.5 micrograms, intrathecal) significantly attenuated thermal hyperalgesia and reduced its duration in comparison to saline-injected rats (P less than 0.05). The receptive field size of nociceptive-specific and wide-dynamic-range neurons in the superficial and deep spinal dorsal horn recorded 24 h after injection of CFA was significantly reduced to 73 +/- 6% (P less than 0.05, n = 8) and 74 +/- 4% (P less than 0.05, n = 8) of control values, respectively, by a cumulative dose of 3 mg/kg of MK-801 (i.v.). MK-801 (2 mg/kg) prevented the expansion of the receptive fields of dorsal horn neurons recorded 5 +/- 0.4 h (n = 5) after intradermal injection of CFA as compared to saline-injected rats (P less than 0.05). MK-801 had no significant effect on receptive field size of dorsal horn neurons in rats without CFA-induced inflammation but blocked a transient expansion of the receptive fields induced by 1 Hz, C-fiber intensity electrical stimulation of the sciatic nerve. The background activity and noxious heat-evoked response of dorsal horn neurons in rats with CFA-induced inflammation were primarily inhibited and noxious pinch-evoked activity was both facilitated and inhibited by the administration of MK-801. These results support the hypothesis that NMDA receptors are involved in the dorsal horn neuronal plasticity and behavioral hyperalgesia that follows peripheral tissue inflammation.


Asunto(s)
Conducta Animal/efectos de los fármacos , Maleato de Dizocilpina/farmacología , Hiperalgesia/fisiopatología , Mielitis/patología , Médula Espinal/efectos de los fármacos , Animales , Estimulación Eléctrica , Adyuvante de Freund , Masculino , Mielitis/inducido químicamente , Mielitis/fisiopatología , Neuronas/efectos de los fármacos , Neuronas/fisiología , Dolor , Estimulación Física , Ratas , Médula Espinal/patología
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