RESUMEN
A series of double-blind, placebo-controlled clinical trials demonstrated that low doses of morphine (0.4, 1.2, and 3.6 mg) administered into the intraligamentary space of a chronically inflamed hyperalgesic tooth produced a dose-related naloxone-reversible analgesia. This analgesic effect is mediated by a local mechanism in the inflamed tissue, because subcutaneous administration of a 1.2 mg dose of morphine failed to elicit an analgesic response. In contrast, submucosal administration of 1.2 mg morphine or 50 microg fentanyl to the site of extraction of an impacted third molar after the onset of acute pain failed to elicit an analgesic response despite demonstration of a sensitive bioassay. These data indicate that peripheral opioid analgesia can be evoked in a model of chronic, but not acute, inflammatory pain, suggesting a temporal dependent mechanism needed for the expression of peripheral opiate analgesia during inflammation in humans.
Asunto(s)
Analgésicos Opioides/farmacología , Dolor Postoperatorio/tratamiento farmacológico , Periodontitis/complicaciones , Extracción Dental/efectos adversos , Odontalgia/tratamiento farmacológico , Enfermedad Aguda , Adulto , Analgésicos Opioides/administración & dosificación , Enfermedad Crónica , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Fentanilo/farmacología , Humanos , Inyecciones , Masculino , Mepivacaína/farmacología , Morfina/farmacología , Naloxona/farmacología , Dimensión del Dolor , Dolor Postoperatorio/etiología , Factores de Tiempo , Odontalgia/etiología , Resultado del TratamientoRESUMEN
Bradykinin is a potent mediator of pain and inflammation. To examine extracellular levels of bradykinin in human dental pulp, CMA/20 microdialysis probes were inserted into the pulp tissue of 22 teeth diagnosed with normal pulp or with irreversible pulpitis before their extraction or endodontic therapy. Probes were perfused with a modified Locke-Ringer's buffer and bradykinin levels in the dialysate evaluated using a radioimmunoassay. Mean extracellular levels of bradykinin within pulp tissue diagnosed with irreversible pulpitis were significantly higher (262.26 +/- 83.79 fmol/ml) than that found within normal pulp (19.41 +/- 6.47 fmol/ml). Highest levels of bradykinin were detected in pulp tissue diagnosed with irreversible pulpitis when the patient had reported pain in the past, compared with patients who were in pain just before their visit. These observations suggest that the bradykinin system is activated during pulpitis and may contribute to pain and inflammation.
