In teleosts, changes in swimming, exploring, general locomotor activity, and anxious state can be a response to stress mediated by the corticotropin-releasing hormone system activation and its effects on glucocorticoid levels. Zebrafish has been widely used to study neuropharmacology and has become a promising animal model to investigate neurobehavioral mechanisms of stress. In this report the animals were submitted to acute restraint stress for different time lengths (15, 60 and 90 min) for further evaluation of behavioral patterns, whole-body cortisol content, and corticotropin-releasing hormone expression. The results demonstrated an increase in the locomotor activity and an alteration in the swimming pattern during a 5-min trial after the acute restraint stress. Interestingly, all groups of fish tested in the novel tank test exhibited signs of anxiety as evaluated by the time spent in the bottom of the tank. Whole-body cortisol content showed a positive correlation with increased behavioral indices of locomotion in zebrafish whereas molecular analysis of corticotropin-releasing hormone showed a late reduction of mRNA expression (90 min). Altogether, we present a model of acute restraint stress in zebrafish, confirmed by elevated cortisol content, as a valid and reliable model to study the biochemical basis of stress behavior, which seems to be accompanied by a negative feedback of corticotropin-release hormone mRNA expression.

Parkinson's disease (PD) is one of the most prevalent neurodegenerative disease displaying negative impacts on both the health and social ability of patients and considerable economical costs. The classical anti-parkinsonian drugs based in dopaminergic replacement are the standard treatment, but several motor side effects emerge during long-term use. This mini-review presents the rationale to several efforts from pre-clinical and clinical studies using adenosine receptor antagonists as a non-dopaminergic therapy. As several studies have indicated that the monotherapy with adenosine receptor antagonists reaches limited efficacy, the usage as a co-adjuvant appeared to be a promising strategy. The formulation of multi-targeted drugs, using adenosine receptor antagonists and other neurotransmitter systems than the dopaminergic one as targets, have been receiving attention since Parkinson's disease presents a complex biological impact. While pharmacological approaches to cure or ameliorate the conditions of PD are the leading strategy in this area, emerging positive aspects have arisen from non-pharmacological approaches and adenosine function inhibition appears to improve both strategies.

ABSTRACT. Biological cycle of Simpulopsis ovata (Gastropoda, Bulimulidae) in São Francisco de Paula, Rio Grande do Sul, Brazil. The population growth of Simpulopsis ovata (Sowerby, 1822) from the Centro de Pesquisas e Conservação da Natureza -Pró-Mata, São Francisco de Paula, Rio Grande do Sul, Brazil, was studied along eleven months of 1996. Two discontinuous age classes were identified. The first one, with a monthly growth rate of 1.55 mm, was reproductively mature during April and May. The second one appeared after the previous group and had a monthly growth rate of 0.44 mm. The fact that no adults from the two age classes were found together is a characteristic of a semelparous species. New insights about its shell, pallial cavity and reproductive system are given. This is the first record of S. ovata for the State of Rio Grande do Sul.

No abstract

2017-08-25T16:28:27