Efeito dos B-bloqueadores na dor da articulação temporomandibular de ratos e humanos e sua modulação pelos hormônios

Temporomandibular disorder (TMD) is a collective term embracing a number of clinical problems that involve the masticatory muscles, and the temporomandibular joint (TMJ), commonly associated with inflammation. Despite anti-inflammatory drugs (NSAIDs) are frequently used in the control of inflammatory pain, it is well known that inflammatory pain has a sympathetic component that might predominate in the cases less responsive to NSAIDs treatments. Therefore, the aims of this study were: (i) to evaluate whether gonadal hormones modulate the antinociceptive responsiveness to the blockade of ?-adrenoreceptors (ARs) in the TMJ of rats, (ii) to evaluate whether one and three days of treatment with the nonselective ?1 and ?2-AR antagonist nadolol would reduce clinical pain symptoms in TMD patients significantly more than placebo, (iii) to evaluate whether women would experience relatively greater benefit from nadolol than men depending on their hormonal status, and (iv) compared the effect of nadolol with the effect of ibuprofen. The first aim was developed in male and female rats, intact or gonadectomized (with or without hormone replacement), by coadministration of formalin and specific antagonist for ?1, ?2 and ?3-ARs in the TMJ region. The nocieptive behavior was quantified and used for estatistical analysis. For the second aim Nadolol (40 mg/day), ibuprofen (400 mg/day) or placebo was administrated in 27 women not using oral contraceptive (OC), 28 women using OC, and 29 men which met the Research Diagnostic Criteria for TMD. They completed a randomized, crossover, double¿blind, placebo controlled study. Women participated for three months (during menstrual phase and during peri-ovulatory phase in women not using OC, and during menstrual phase and during OC using phase in women using OC) in a total of 6 stages of analysis (2 per month), and men participated for one month whith three stages of analysis and 6 days of wash out. Each stage consisted of a baseline evaluation and two evaluations during treatment, one on the first and the other on the third day of treatment. Clinical pain ratings were obtained by Visual Analog Scale (VAS) and comparisons were made across the pre-treatment (baseline), the first and the third day of intervention (post-treatment). Blockade of ?-ARs significantly reduce the TMJ nociception in male and female rats, but females are more responsive. The gonadal hormones reduce the responsiveness to the blockade of ?-ARs in the TMJ of males and females rats. In the human study one and three days of treatment with nadolol or ibuprofen produces analgesia in TMD women and men significantly more than placebo, but women are more responsive independent of their hormonal status. In summary, these data demonstrate that gonadal hormones can modulate the analgesic effect of ?-ARs blockers depending on the gonadal hormones serum levels, on the ?-ARs activated subtype and on the dose of drug administered. The greater treatment efficacy in women is of clinical relevance since TMD is more prevalent and severe in women than in men (AU)