Frederico Guilherme Graeff

Learn More
Behavioral categories were measured in rats left on an elevated plus-maze for 5 min, in addition to the traditional measures. Four independent factors emerged from a factor analysis. The variables that loaded highly and positively on Factor 1, seemingly related with anxiety, were: number of entries onto open arms, time spent on open arms, percentage of(More)
There are conflicting results on the function of 5-HT in anxiety and depression. To reconcile this evidence, Deakin and Graeff have suggested that the ascending 5-HT pathway that originates in the dorsal raphe nucleus (DRN) and innervates the amygdala and frontal cortex facilitates conditioned fear, while the DRN-periventricular pathway innervating the(More)
Anxiety disorders are heterogeneous and existing animal models do not discriminate specific types of anxiety. The elevated T-maze is being developed to fulfill this purpose. The apparatus consists of three elevated arms, one enclosed and two open. Inhibitory avoidance--representing learned fear--is measured by recording the time taken to leave the enclosed(More)
This review covers the effect of drugs affecting anxiety using four psychological procedures for inducing experimental anxiety applied to healthy volunteers and patients with anxiety disorders. The first is aversive conditioning of the skin conductance responses to tones. The second is simulated public speaking, which consists of speaking in front of a(More)
The elevated T-maze is an animal model of anxiety, consisting of three elevated arms: one enclosed and two open. Inhibitory avoidance of the open arms-representing learned fear-has been related to generalized anxiety and the unconditioned escape from one of the open arms to panic. In the present study, we investigated the effects of acute and chronic (21(More)
1. There is suggestive evidence that the septo-hippocampal system and the amygdala are involved in risk assessment behavior, a response to potential threat possibly related to anxiety. In addition, experimental results have been reported implicating the medial hypothalamus in coordinated escape, while the periaqueductal gray matter (PAG) and the median(More)
In an attempt to analyze different types of anxiety, and at the same time assess memory, a new experimental model was developed. The apparatus, named the elevated T-maze, consisted of three arms of equal dimensions (50 x 10 cm) elevated 50 cm from the ground. One arm, enclosed by 40-cm high walls, was perpendicular to two open arms. The first experimental(More)
A factor analysis of the scores from rats given two trials in the elevated plus-maze showed that four independent factors emerged. Measures of anxiolytic activity on trial 1 (number of open arm entries and time spent on open arms) loaded on factor 1, measures of anxiolytic activity on trial 2 loaded on factor 2, the measure of general activity (number of(More)
To explore the role of 5-HT receptor subtypes in controlling aversion, we measured the effect of 5-HT1A and 5-HT2A/2C receptor agonists microinjected into the dorsal periaqueductal gray (DPAG) of rats on aversive behavior induced by electrical stimulation of the same brain area. The 5-HT1A agonists 8-OH-DPAT (4-16 nmol) and BAY-R-1531 (4-16 nmol) raised the(More)