According to the parameter used in this study, LPT produced analgesia. Analgesia induced by laser phototherapy is mediated by peripheral opioid receptors. Laser phototherapy does not seem to interact with peripheral serotonergic receptors.

Peres e Serra A, Parra ER, Eher E, Capelozzi VL. Nonhomogeneous Immunostaining of hyaline membranes in different manifestations of diffuse alveolar damage. CLINICS. 2006;61(6):497-502. PURPOSE:To determine the nature of hyaline membranes in different manifestations of diffuse alveolar damage, [pulmonary and extrapulmonary acute respiratory distress syndrome], and idiopathic [acute interstitial pneumonia]. MATERIALS AND METHODS: Pulmonary specimens were obtained from 17 patients with acute respiratory distress syndrome and 9 patients with acute interstitial pneumonia. They were separated into 3 different groups: (a) pulmonary diffuse alveolar damage (pDAD) (n = 8), consisting only of pneumonia cases; (b) extrapulmonary diffuse alveolar damage (expDAI) (n = 9), consisting of sepsis and septic shock cases; and (c) idiopathic diffuse alveolar damage (iDAD) (n = 9), consisting of idiopathic cases (acute interstitial pneumonia). Hyaline membranes, the hallmark of the diffuse alveolar damage histological pattern, were examined using various kinds of antibodies. The antibodies used were against surfactant apoprotein-A (SP-A), cytokeratin 7 (CK7), cytokeratin 8 (CK8), alpha smooth muscle actin (α-SMA), cytokeratin AE1/AE3 (AE1/AE3), and factor VIII-related antigen (factor VIII). RESULTS: Pulmonary diffuse alveolar damage showed the largest quantity of hyaline membranes (12.65% ± 3.24%), while extrapulmonary diffuse alveolar damage (9.52% ± 3.64%) and idiopathic diffuse alveolar damage (7.34% ± 2.11%) showed intermediate and lower amounts, respectively, with the difference being statistically significant between pulmonary and idiopathic diffuse alveolar damage (P < 0.05). No significant difference was found for hyaline membranes Sp-A immunostaining among pulmonary (15.36% ± 3.12%), extrapulmonary (16.12% ± 4.58%), and idiopathic (13.74 ± 4.20%) diffuse alveolar damage groups. Regarding factor VIII, we found that idiopathic diffuse alveolar damage presented larger amounts of immunostained hyaline membranes (14.12% ± 6.25%) than extrapulmonary diffuse alveolar damage (3.93% ± 2.86%), with this difference being statistically significant (P < 0.001). Equally significant was the difference for progressive decrease of cytokeratin AE1/AE3 immunostaining in hyaline membranes present in the extrapulmonary diffuse alveolar damage (5.42% ± 2.80%) and idiopathic diffuse alveolar damage (0.47% ± 0.81%) groups (P < 0.001). None of the groups stained for cytokeratin CK-7, CK-8, vimentin, or α anti-smooth muscle actin. CONCLUSIONS: This study showed that only the epithelial/endothelial components (SP-A, factor VIII, and AE1/AE3) of the alveolar/capillary barrier are present in hyaline membranes formation in the 3 groups of patients with diffuse alveolar damage. The significant difference in the expression of factor VIII-related antigen and cytokeratin AE1/AE3 in the expDA versus iDAD groups as well as the significant difference in the amount of hyaline membranes present in the pDAD versus iDAD groups are suggestive of a local and specifi...

Summary: Serra AP, Ashmawi HA -Influence of Naloxone and Methysergide on the Analgesic Effects of Low-Level Laser in an Experimental Pain Model. Background and objectives:Although the mechanism of action of laser phototherapy (LPT) is not known, it is a promising analgesic method. The aim of this study was to evaluate whether the action of LPT depends on the activation of peripheral opioid or serotonergic receptors.