Antinociceptive properties in mice of a lectin isolated from the marine alga Amansia multifida Lamouroux.

The antinociceptive effects of a lectin (LEC) isolated from the marine alga Amansia multifida were determined in Swiss mice. The LEC (1, 5, and 10 mg/kg) inhibited acetic acid-induced abdominal writhings in a dose-dependent manner after intraperitoneal or oral administration. A partial but significant inhibition of writhings was observed after the combination of LEC (10 mg/kg) with avidin (1 mg/kg), a potent inhibitor of the hemmaglutinant activity of the lectin. However, total writhing inhibition was demonstrable in the group of mice treated with LEC plus mannose (1 mg/kg), as compared to LEC alone or to control groups. Furthermore, avidin and mainly mannose also play a role in antinociception, somehow facilitating the interaction of LEC with its active cell sites. In the formalin test, although both phases of the response were significantly inhibited, the effect of LEC was predominant during phase 2, causing inhibition of licking time that ranged from 48 to 88% after oral (5 and 10 mg/kg) and intraperitoneal (1 to 5 mg/kg) administration. As is the case with morphine, the effect of LEC (2 mg/kg) was reversed by naloxone (2 mg/kg), indicating the involvement of the opioid system. LEC was also effective in the hot-plate test, producing inhibitory responses to the thermal stimulus, and its effects were blocked by naloxone. In the pentobarbital-induced sleeping time, although LEC did not alter the onset of sleep significantly, it increased the time of sleep within the same dose range compared to control. These results show that LEC presents antinociceptive effects of both central and peripheral origin, possibly involving the participation of the opioid system.

Antinociceptive properties in mice of a lectin isolated from the marine alga Amansia multifida Lamouroux

The antinociceptive effects of a lectin (LEC) isolated from the marine alga Amansia multifida were determined in Swiss mice. The LEC (1, 5, and 10 mg/kg) inhibited acetic acid-induced abdominal writhings in a dose-dependent manner after intraperitoneal or oral administration. A partial but significant inhibition of writhings was observed after the combination of LEC (10 mg/kg) with avidin (1 mg/kg), a potent inhibitor of the hemmaglutinant activity of the lectin. However, total writhing inhibition was demonstrable in the group of mice treated with LEC plus mannose (1 mg/kg), as compared to LEC alone or to control groups. Furthermore, avidin and mainly mannose also play a role in antinociception, somehow facilitating the interaction of LEC with its active cell sites. In the formalin test, although both phases of the response were significantly inhibited, the effect of LEC was predominant during phase 2, causing inhibition of licking time that ranged from 48 to 88 percent after oral (5 and 10 mg/kg) and intraperitoneal (1 to 5 mg/kg) administration. As is the case with morphine, the effect of LEC (2 mg/kg) was reversed by naloxone (2 mg/kg), indicating the involvement of the opioid system. LEC was also effective in the hot-plate test, producing inhibitory responses to the thermal stimulus, and its effects were blocked by naloxone. In the pentobarbital-induced sleeping time, although LEC did not alter the onset of sleep significantly, it increased the time of sleep within the same dose range compared to control. These results show that LEC presents antinociceptive effects of both central and peripheral origin, possibly involving the participation of the opioid system.

Neutrophil migration induced in vivo and in vitro by marine algal lectins.

OBJECTIVE AND DESIGN: Since some plant and mammalian lectins specific for monosaccharides are able to induce neutrophil migration, we studied the neutrophil migration-inducing activities of marine algal lectins, specific for complex oligosaccharides from glycoproteins, from Amansia multifida (AM), Bryothamnion seaforthii (BS), Bryothamnion triquetrum (BT) and Gracilaria caudata (GC). MATERIALS AND METHODS: The neutrophil migration-inducing activity of AM, BS, BT and GC was assayed in vitro and in vivo in the peritoneal cavity or dorsal air pouch of rats or mice, and was inhibited by glycans. RESULTS: AM, BS, BT and GC induced neutrophil migration in vivo and in vitro, determining bell-shaped dose-dependent curves. Maximal neutrophil influx was determined by BT in rats and by AM in mice. Maximal human neutrophil chemotaxis was obtained with GC. These activities were not inhibited by glycoproteins previously identified as being recognized by these lectins. D-mannose was a strong inhibitor, especially of BT activity both in vitro and in vivo. CONCLUSIONS: Algal lectins induced neutrophil migration, which was inhibited by a monosaccharide, contrasting with the view that they only recognize complex oligosaccharides. Neutrophil chemotaxis assays are appropriate to study low molecular mass lectins containing a single carbohydrate recognition domain, as is the case of some lectins from algae and mammals.

[Acute Chagas cardiopathy. A systematic study of the intracardiac excitatory-conduction and autonomic nervous systems in an autochthonous case in Acre]. / Contribuição ao conhecimento da cardiopatia chagásica aguda. Estudo sistematizado dos sistemas excito-condutor e nervoso autônomo intracardíaco em caso autóctone do Acre.

The histopathology of the heart is described in an acute case of Chagas' disease (DC). Lesions involving the conducting system (SC) and the autonomic intracardiac nervous system (SNAIC) are emphasized. Light microscopy showed acute pan-carditis with plenty of Trypanosoma cruzi amastigotes within heart muscle cells. Multiple inflammatory foci were found in the SC with parasitic nests within the atrioventricular node and left his bundle. There were also severe atrial periganglionitis and perineuritis with or without peripheral involvement of those structures. Apparently there was no cardiac neuronal depopulation. The epidemiological study suggested transmission through Rhodnius pictipes. To the best of our knowledge, this is the first reported case of acute DC from the Amazonian basin with systematized microscopy study of the SC and SNAIC.