Organization of single components of defensive behaviors within distinct columns of periaqueductal gray matter of the rat: role of N-METHYL-d-aspartic acid glutamate receptors

Bittencourt, Athelson Stefanon; Carobrez, A.P.; Zamprogno, L.P.; Tufik, Sérgio; Schenberg, Luiz Carlos

doi:10.1016/j.neuroscience.2004.01.026

Cited by 134 publications

(114 citation statements)

References 66 publications

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“…The PAG is divided into rostro-caudal columns that have been proposed to control different behavioral outputs (Bittencourt et al 2004). The dorsal columns of the PAG (PAGd) represent the main output structures of the medial hypothalamic defensive system (Canteras et al 1994;Canteras 2002;Gross and Canteras 2012) as well as of the SC and IC (Canteras et al 1992) and mediate active defensive responses to imminent threats like predators and aggressive conspecifics (Sukikara et al 2006;Motta et al 2009;Silva et al 2013).…”

Section: Pag: a Common Output For Defensementioning

confidence: 99%

The neural circuits of innate fear: detection, integration, action, and memorization

2016

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How fear is represented in the brain has generated a lot of research attention, not only because fear increases the chances for survival when appropriately expressed but also because it can lead to anxiety and stress-related disorders when inadequately processed. In this review, we summarize recent progress in the understanding of the neural circuits processing innate fear in rodents. We propose that these circuits are contained within three main functional units in the brain: a detection unit, responsible for gathering sensory information signaling the presence of a threat; an integration unit, responsible for incorporating the various sensory information and recruiting downstream effectors; and an output unit, in charge of initiating appropriate bodily and behavioral responses to the threatful stimulus. In parallel, the experience of innate fear also instructs a learning process leading to the memorization of the fearful event. Interestingly, while the detection, integration, and output units processing acute fear responses to different threats tend to be harbored in distinct brain circuits, memory encoding of these threats seems to rely on a shared learning system.

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Section: Pag: a Common Output For Defensementioning

confidence: 99%

The neural circuits of innate fear: detection, integration, action, and memorization

2016

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“…Intra-dlPAG injection of NO donors or glutamate agonists induces flight reactions similar to unconditioned fear responses to proximal danger (Aguiar et al, 2006;Bittencourt et al, 2004;Krieger and Graeff, 1985). Moreover, predator exposure increases NO production (Chiavegatto et al, 1998) and induces Fos expression in NADPH-D-positive neurons (a marker of nitric oxide synthase [NOS] presence) in this region, an effect prevented by intracerebroventricular (i.c.v.)…”

mentioning

confidence: 99%

Blockade of NMDA receptors and nitric oxide synthesis in the dorsolateral periaqueductal gray attenuates behavioral and cellular responses of rats exposed to a live predator

Aguiar

Guimarães

2009

J of Neuroscience Research

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Innate fear stimulus induces activation of neurons containing the neuronal nitric oxide synthase enzyme (nNOS) in defensive-related brain regions such as the dorsolateral periaqueductal gray (dlPAG). Intra-dlPAG administration of nitric oxide synthase (NOS) inhibitors and glutamate antagonists induce anxiolytic-like responses. We investigated the involvement of nitric oxide (NO) and glutamate neurotransmission in defensive reactions modulated by dlPAG. We tested if intra-dlPAG injections of the selective nNOS inhibitor, N-propyl-L-arginine (NP), or the glutamate antagonist, AP7 (2-amino-7-phosphonoheptanoic acid), would attenuate behavioral responses and cellular activation induced by predator exposure (cat). Fos-like immunoreactivity (FLI) was used as a marker of neuronal functional activation, whereas nNOS immunohistochemistry was used to identify NOS neurons. Cat exposure induced fear responses and an increase of FLI in the dlPAG and dorsal premammillary nucleus (PMd). NP and AP7 attenuated the cat-induced behavioral responses. Whereas NP tended to attenuate FLI in the dlPAG, AP7 induced a significant reduction in cellular activation of this region. The latter drug, however, increased FLI and double-labeled cells in the PMd. Cellular activation of this region was significantly correlated with time spent near the cat (r = 0.7597 and 0.6057 for FLI and double-labeled cells). These results suggest that glutamate/NO-mediated neurotransmission in the dlPAG plays an important role in responses elicit by predator exposure. Blocking these neurotransmitter systems in this brain area impairs defensive responses. The longer time spent near the predator that follows AP7 effect could lead to an increased cellular activation of the PMd, a more rostral brain area that has also been related to defensive responses.

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“…It has now been well documented that mGlu 1 receptors and the glutamatergic system represent tractable targets for treating these common disorders (Bittencourt et al, 2004;Paul and Skolnick, 2003).…”

Section: Mglu 1 In Anxiety and Depressionmentioning

confidence: 99%

Metabotropic Receptors for Glutamate and GABA

Stewart¹,

Kniazeff²,

Prézeau³

et al. 2012

Pharmacology

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Organization of single components of defensive behaviors within distinct columns of periaqueductal gray matter of the rat: role of N-METHYL-d-aspartic acid glutamate receptors

Cited by 134 publications

References 66 publications

The neural circuits of innate fear: detection, integration, action, and memorization

The neural circuits of innate fear: detection, integration, action, and memorization

Blockade of NMDA receptors and nitric oxide synthesis in the dorsolateral periaqueductal gray attenuates behavioral and cellular responses of rats exposed to a live predator

Metabotropic Receptors for Glutamate and GABA

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