4 research outputs found
Gonadal Hormones Modulate The Responsiveness To Local β-blocker-induced Antinociception In The Temporomandibular Joint Of Male And Female Rats.
We have previously demonstrated that blockade of β-adrenoreceptors (β-AR) located in the temporomandibular joint (TMJ) of rats suppresses formalin-induced TMJ nociceptive behaviour in both male and female rats, but female rats are more responsive. In this study, we investigated whether gonadal hormones modulate the responsiveness to local β-blocker-induced antinociception in the TMJ of rats. Co-administration of each of the selective β1 (atenolol), β2 (ICI 118.551) and β3 (SR59230A)-AR antagonists with equi-nociceptive concentrations of formalin in the TMJ of intact, gonadectomized and hormone-treated gonadectomized male and female rats. Atenolol, ICI 118.551 and SR59230A significantly reduced formalin-induced TMJ nociception in a dose response fashion in all groups tested. However, a lower dose of each β-AR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact and testosterone-treated gonadectomized male rats. In the female groups, a lower dose of β1 -AR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact or gonadectomized rats treated with progesterone or a high dose of oestradiol; a lower dose of β2 -AR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact and gonadectomized rats treated with low or high dose of oestradiol. Gonadal hormones may reduce the responsiveness to local β-blocker-induced antinociception in the TMJ of male and female rats. However, their effect depends upon their plasma level, the subtype of β-AR and the dose of β-blockers used
Gonadal hormones modulate the responsiveness to local βâblockerâinduced antinociception in the temporomandibular joint of male and female rats
We have previously demonstrated that blockade of βâadrenoreceptors (βâAR) located in the temporomandibular joint (TMJ) of rats suppresses formalinâinduced TMJ nociceptive behaviour in both male and female rats, but female rats are more responsive. In this study, we investigated whether gonadal hormones modulate the responsiveness to local βâblockerâinduced antinociception in the TMJ of rats. Methods Coâadministration of each of the selective β1 (atenolol), β2 (ICI 118.551) and β3 (SR59230A)âAR antagonists with equiânociceptive concentrations of formalin in the TMJ of intact, gonadectomized and hormoneâtreated gonadectomized male and female rats. Results Atenolol, ICI 118.551 and SR59230A significantly reduced formalinâinduced TMJ nociception in a dose response fashion in all groups tested. However, a lower dose of each βâAR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact and testosteroneâtreated gonadectomized male rats. In the female groups, a lower dose of β1âAR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact or gonadectomized rats treated with progesterone or a high dose of oestradiol; a lower dose of β2âAR antagonist was sufficient to significantly reduce nociceptive responses in gonadectomized but not in intact and gonadectomized rats treated with low or high dose of oestradiol. Conclusion Gonadal hormones may reduce the responsiveness to local βâblockerâinduced antinociception in the TMJ of male and female rats. However, their effect depends upon their plasma level, the subtype of βâAR and the dose of βâblockers used196772780FUNDAĂĂO DE AMPARO Ă PESQUISA DO ESTADO DE SĂO PAULO - FAPESP2009/16991-0; 2010/19872-