Effect of domoic acid on metabolism of 5-hydroxytryptamine in rat brain

Domoic acid (Dom) is a neurotoxic secondary amino acid that interacts with the glutamate receptors, producing neurological problems. In the present work, we study the effects of Dom on the levels of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in discrete rat brain regions. The effects of Dom on the brain metabolism of serotonin are also discussed in this paper. Dom stimulates the rat brain serotoninergic system, increasing differentially the synthesis and the catabolism of 5-HT and the elimination of 5-HIAA.

Effect of domoic acid on brain amino acid levels

The administration of Domoic Acid (Dom) in a 0.2 mg/kg i.p. dose induces changes in the levels of amino acids of neurochemical interest (Asp, Glu, Gly, Tau, Ala, GABA) in different rat brain regions (hypothalamus, hippocampus, amygdala, striatum, cortex and midbrain). The most affected amino acid is the GABA, the main inhibitory amino acid neurotransmitter, whereas glutamate, the main excitatory amino acid, is not affected. The rat brain regions that seem to be the main target of the Dom action belong to the limbic system (hippocampus, amygdala). The possible implication of the amino acids in the actions of Dom is also discussed.

[Blastocystis hominis: frequency of infection in ambulatory patients from the northern section of Santiago, Chile]

In July 1989-July 1990 period, a coproparasitological study of 6,162 ambulatory patients from the northern section of Santiago, was undertaken. Out of the total number of the studied individual, 88.6% were children, (51.4% females and 48.6% males). The global frequency of infection by B. hominis was 30.4%. In relation to age. Blastocystis hominis was found in: 13.1% of the group of children (1 month-2 years); 34.1% of the pre-school children, 45.4% in the school-children and 43.0% in the adults. B. hominis was frequently detected in association with other parasites and/or commensals, and observed alone in the 6.0% of the studied patients.

[Incidence of infection by intestinal parasites among school children in Santiago, Chile, 1988-1989]

In December 1988-February 1989 period, a survey on enteroparasitic infections in children (mean age 8.7 years; males 54.4% and females 45.6%) from five schools located in Santiago, Chile, was undertaken. To each of these individuals, three samples were obtained in order to perform in them the following examinations: co-proparasitological study, modified Ziehl-Neelsen staining for detecting Cryptosporidium sp. and cellulose adhesive test for Enterobius vermicularis. Parasitic elements were found in the following percentages: Blastocystis hominis 51.8, Enterobius vermicularis 39.9, Giardia lamblia 32.1, Entamoeba histolytica 7.8, Hymenolepis nana 2.1 and Ascaris lumbricoides 0.4, Cryptosporidium sp. were not observed. The present study would be demonstrating that enteroparasites maintain their endemic condition among school children from Santiago, including B. hominis which had not been searched previously.