Leda Menescal-de-Oliveira

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Tonic immobility (TI) is an innate defensive behaviour elicited by physical restriction and postural inversion, and is characterised by a profound and temporary state of akinesis. Our previous studies demonstrated that glutamatergic stimulation of the dorsomedial/dorsolateral portion of periaqueductal gray matter (dPAG) decreases the duration of TI in(More)
Tonic immobility (TI) is an innate defensive behavior characterized by a state of physical inactivity and diminished responsiveness to environmental stimuli. Behavioral adaptations to changes in the external and internal milieu involve complex neuronal network activity and a large number of chemical neurotransmitters. The TI response is thought to be(More)
Tonic immobility is an inborn defensive behavior characterized by a temporary state of profound and reversible motor inhibition elicited by some forms of physical restraint. The periaqueductal gray matter (PAG) contains neural circuits involved in descending pain modulation, as well as in the modulation of TI. We have reported previously that the(More)
AIMS Several physiological, pharmacological and behavioral lines of evidence suggest that the hippocampal formation is involved in nociception. The hippocampus is also believed to play an important role in the affective and motivational components of pain perception. Thus, our aim was to investigate the participation of cholinergic, opioidergic and(More)
Tonic immobility (TI), also known as death feigning or animal hypnosis, is a reversible state of motor inhibition that is not only triggered by postural inversion and/or movement restraining maneuvers but also by repetitive stimulation and pressure on body parts. Evidence has demonstrated that the basolateral nucleus of the amygdala (BLA) is particularly(More)
Tonic immobility (TI) is a temporary state of profound motor inhibition induced by situations that supposedly generate intense fear, with the objective to protect the animal from attacks by predators. A previous study by our group demonstrated that cholinergic stimulation of the central, basolateral, and lateral posterior nuclei of the amygdala decreases(More)
Several studies have demonstrated the involvement of the central nucleus of the amygdala (CEA) in the modulation of defensive behavior and in antinociceptive regulation. In a previous study, we demonstrated the existence of a cholinergic-opioidergic interaction in the CEA, modulating the defensive response of tonic immobility in guinea pigs. In the present(More)
Ascending nociceptive control is a novel spino-striato-rostral ventral medulla pain modulation pathway that mediates heterosegmental pain-induced analgesia, i.e., noxious stimulus-induced antinociception. In this study, we used the dorsal immobility response in rats as a model of the defensive responses. We demonstrated that the activation of ascending(More)
Unilateral microinjection of carbachol (1 microgram) into the dorsal parabrachial region (PBR) of conscious guinea pigs produced a 100% increase in the duration of restraint-induced tonic immobility (TI) episodes. In another group of animals with a subcutaneous electrode introduced into the thigh region, microinjections of equivalent doses of the same drug(More)
Unilateral microinjection of carbachol (CCh, 1.0 microg/0.2 microl) into the ventrolateral periaqueductal gray matter (vPAG) increased the duration of tonic immobility (TI) episodes induced by postural inversion and by movement restriction maneuvers in adult male guinea pig (Cavia porcellus), while stimulation with the same drug at the same concentration(More)