Defensive reactions evoked by activation of NMDA receptors in distinct sites of the inferior colliculus

Cardoso, Sílvia Helena; Coimbra, Norberto Cysne; Brandão, Marcus Lira

doi:10.1016/0166-4328(94)90046-9

Cited by 81 publications

(33 citation statements)

References 44 publications

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“…In fact, the IC is a key pathway for auditory information and disturbances at this level may alter the transmission to cortical centers. An indirect pathway connecting these structures is given by projections from the central nucleus of the IC-medial geniculate nucleusamygdala-dorsomedial thalamus-prefrontal cortex (Fuster, 1989;Brodal, 1992;Cardoso et al, 1994). It has been shown that this alternate circuit is concerned with the processing of auditory information of aversive nature, which triggers fear-like behaviors (LeDoux et al, 1990;Maisonnette et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

“…The inferior colliculus (IC) is a midbrain tectum structure primarily involved in auditory information processing; it also integrates sensory information of aversive nature. Indeed, electrical or chemical stimulation of this structure induces responses such as freezing and flight responses that mimic fearful behavior elicited by environmental challenges (Schmitt et al, 1986;Brandão et al, 1988Cardoso et al, 1994;Troncoso et al, 1998;Castilho et al, 1999). Several studies have suggested modulatory roles for GABA, serotonin, opioids, excitatory amino acids and neuropeptides at the so-called brain aversion system, which includes the dorsal periaqueductal gray and IC (Brandão et al, 1982.…”

Section: Introductionmentioning

confidence: 99%

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Apomorphine Enhances Conditioned Responses Induced by Aversive Stimulation of the Inferior Colliculus

Troncoso¹,

Osaki²,

Mason³

et al. 2003

Neuropsychopharmacol

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Consistent evidence has shown that learning may be produced in paradigms using electrical stimulation of the inferior colliculus (IC) as unconditioned stimulus (UCS). Recent reports have also demonstrated that aversive stimulation of the IC, at the escape threshold, enhances dopamine (DA) release in the prefrontal cortex. The purpose of the present study was to determine whether dopaminergic mechanisms are involved in the Pavlovian conditioning and latent inhibition using IC stimulation as UCS and light as conditioned stimulus (CS). Rats were placed inside a shuttle box and subjected to a two-way avoidance paradigm. IC aversive electrical stimulation was used as UCS and shuttle box illumination as CS. The rats quickly learned to avoid or interrupt the IC stimulation. Apomorphine injections produced a dose-dependent increase in the number of avoidance responses. On the other hand, chlorpromazine administration promoted a dose-dependent reduction of the avoidance responses. Previous injections of chlorpromazine inhibited the effects of apomorphine. Also, previous exposure to unreinforced light weakened the strength of the conditioning. Apomorphine blocked this latent inhibition effect, which was antagonized by previous injections of chlorpromazine. These findings bring evidence for the involvement of DA in the setting up of adaptive responses to aversive states generated at the IC level, which may underlie stressful situations present in anxiety.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Apomorphine Enhances Conditioned Responses Induced by Aversive Stimulation of the Inferior Colliculus

Troncoso¹,

Osaki²,

Mason³

et al. 2003

Neuropsychopharmacol

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“…This defense response was followed by behavioral changes such as an increase in the number of turnings and a decrease in the number of rearings and grooming episodes. Aversive stimuli such as an electric footshock can induce rotational behavior in rats (14) and it has been suggested that turnings may be part of the defensive repertoire of these animals (15). Rearings are often used to evaluate exploratory activity (16) and a decrease in exploratory drive has been observed in rats submitted to stressful events (17).…”

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confidence: 99%

Defense reaction induced by a metabotropic glutamate receptor agonist microinjected into the dorsal periaqueductal gray of rats

Molchanov

Guimarães

1999

Braz J Med Biol Res

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The behavioral effects of trans-(±)-1-amino-1,3-cyclopentanedicarboxylic acid (t-ACPD), a metabotropic glutamate receptor (mGluR) agonist, or 0.9% (w/v) saline, injected into the dorsal periaqueductal gray (DPAG), was investigated. Male Wistar rats showed defense reactions characterized by jumps toward the top edges of the cages (saline = 0 vs t-ACPD = 6.0, medians P<0.05) and gallops (saline = 0 vs t-ACPD = 10.0, medians P<0.05) during the 60-s period after the beginning of the injection. In another experiment animals were placed inside an open arena for 5 min immediately after injection. Their behavior was recorded by a video camera and a computer program analyzed the videotapes. Eleven of fifteen rats injected with t-ACPD showed a short-lasting (about 1 min) flight reaction. No saline-treated animal showed this reaction (P<0.0005, chi-square test). The drug induced an increase in turning behavior (P = 0.002, MANOVA) and a decrease in the number of rearings (P<0.001, MANOVA) and grooming episodes (P<0.001, MANOVA). These results suggest that mGluRs play a role in the control of defense reactions in the DPAG.

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“…These include glutamate agonists, γ-amino-butyric-acid (GABA), serotonin (5HT), cholecystokinin (CCK) and neuropeptides such as opioids and corticotropin releasing factor (CRF) (Brandao et al, 1999;Brandao, et al, 1982;Cardoso, et al, 1994;Carvalho-Netto, et al, 2007;Graeff, 1997;Jenck, et al, 1986;Melo, et al, 1992). Receptor binding studies have shown a substantial population of both CRF1 and CRF2 in the PAG (Merchenthaler, 1984;Swanson, et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

CRF type 1 receptors in the dorsal periaqueductal gray modulate anxiety-induced defensive behaviors

Litvin

Pentkowski

Blanchard

et al. 2007

Hormones and Behavior

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Defensive reactions evoked by activation of NMDA receptors in distinct sites of the inferior colliculus

Cited by 81 publications

References 44 publications

Apomorphine Enhances Conditioned Responses Induced by Aversive Stimulation of the Inferior Colliculus

Apomorphine Enhances Conditioned Responses Induced by Aversive Stimulation of the Inferior Colliculus

Defense reaction induced by a metabotropic glutamate receptor agonist microinjected into the dorsal periaqueductal gray of rats

CRF type 1 receptors in the dorsal periaqueductal gray modulate anxiety-induced defensive behaviors

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