ABSTRACT
This paper presents an up-to-date review of the evidence indicating that atypical neurotransmitters such as nitric oxide (NO) and endocannabinoids (eCBs) play an important role in the regulation of aversive responses in the periaqueductal gray (PAG). Among the results supporting this role, several studies have shown that inhibitors of neuronal NO synthase or cannabinoid receptor type 1 (CB1) receptor agonists cause clear anxiolytic responses when injected into this region. The nitrergic and eCB systems can regulate the activity of classical neurotransmitters such as glutamate and γ-aminobutyric acid (GABA) that control PAG activity. We propose that they exert a ‘fine-tuning’ regulatory control of defensive responses in this area. This control, however, is probably complex, which may explain the usually bell-shaped dose-response curves observed with drugs that act on NO- or CB1-mediated neurotransmission. Even if the mechanisms responsible for this complex interaction are still poorly understood, they are beginning to be recognized. For example, activation of transient receptor potential vanilloid type-1 channel (TRPV1) receptors by anandamide seems to counteract the anxiolytic effects induced by CB1 receptor activation caused by this compound. Further studies, however, are needed to identify other mechanisms responsible for this fine-tuning effect.
Subject(s)
Animals , Mice , Rats , Anxiety/physiopathology , Escape Reaction/physiology , Neurotransmitter Agents/physiology , Periaqueductal Gray/physiology , Synaptic Transmission/physiology , Anxiety/metabolism , Arachidonic Acids/pharmacology , Cannabinoid Receptor Agonists/pharmacology , Endocannabinoids/pharmacology , Endocannabinoids/physiology , Nitric Oxide/physiology , Periaqueductal Gray/metabolism , Polyunsaturated Alkamides/pharmacology , TRPV Cation Channels/physiologyABSTRACT
The objective of this study is to evaluate the frequency of Trypanosoma cruzi infection among blood donors at the Iguatu Regional Hemocenter, CE, 1996 - 1997, using the Enzyme-linked immunosorbent assay (ELISA) and hemagglutination passive reverse (HPR) tests. Of the 3,232 donors analyzed a total of 61 (1.9%) were seropositive for chagasic infection. The greatest number of infected donors was found in the 41-50 year age group, while the majority of donors were in the 18-30 year age group. Of the total number of donors analyzed 2,991 (92.5%) were men and 57 (1.9%) of these were seropositive. In all 1,825 (56.5 %) of the donors were from a rural area. The results showed that the ELISA test detected 49 cases of infection, but HPR only 38, thereby demonstrating that the use of two or more different tests by blood banks prevents transfusion associated Chagas' disease.
Esse estudo tem como objetivo avaliar a prevalência de infecção pelo Trypanosoma cruzi em doadores de sangue do Hemocentro regional de Iguatu, CE, 1996-1997, usando os testes Ensaio Imunoenzimático (ELISA ) e Hemaglutinação Passiva Reversa (HPR). Dos 3.232 doadores analisados 61 (1,9%) foram soropositivos para a infecção chagásica, onde o maior número de soropositividade foi encontrado no grupo de 41-50 anos, no entanto, o maior número de doadores que procuram o branco de sangue encontra-se na faixa etária de 18-30 anos. Do total de doadores analisados 2.991 (92,5%) foram do sexo masculino e destes 57 (1,9%) foram soropositivos. Com relação a procedência dos doadores observamos que 1.825 (56,5%) foram procedentes da área rural. Os resultados mostram que o ELISA detectou 49 doadores com a infecção e por HPR apenas 38, mostrando portanto que a utilização de dois ou mais testes em bancos de sangue poderá prevenir a transmissão da doença de Chagas associada à transfusão.
Subject(s)
Adolescent , Adult , Female , Humans , Male , Middle Aged , Blood Donors , Chagas Disease/epidemiology , Brazil , PrevalenceABSTRACT
Determina os parametros hematologicos: hemacias, hemoglobulina, hematocrito, indices hematimetricos, reticulocitos e hemossedimentacao, em 200 individuos adultos normais, residentes em Fortaleza, Ceara.Os valores encontrados foram submetidos a analise estatisca e os resultados comparados com os da literatura