The relevance of neuronal substrates of defense in the midbrain tectum to anxiety and stress: empirical and conceptual considerations

Brandão, Marcus Lira; Troncoso, Ana Cristina; Silva, Maria Angélica de Souza; Huston, Joseph P.

doi:10.1016/s0014-2999(03)01284-6

Cited by 145 publications

(95 citation statements)

References 92 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In agreement with Brandão et al (18), the preparatory process of danger-orientation, fear and avoidance seems to be linked to anxiety. Thus, the facilitatory effect of CPA on memory reported here can also be due to an anxiolyticlike effect of CPA mediated by the diencephalon and/or the midbrain tectum.…”

supporting

confidence: 91%

Chlorpheniramine facilitates inhibitory avoidance in teleosts submitted to telencephalic ablation

Faganello

Mattioli

2008

Braz J Med Biol Res

View full text Add to dashboard Cite

The present study investigated the involvement of H(1) histaminegic receptor on the acquisition of inhibitory avoidance in Carassius auratus submitted to telencephalic ablation. The fish were submitted to telencephalic ablation 5 days before the experiment. The inhibitory avoidance procedure included 1 day for habituation, 3 days for training composed of 3 trials each (1st day: T1, T2, T3; 2nd day: 2T1, 2T2, 2T3; 3rd day: 3T1, 3T2, 3T3) and 1 day for test. On training days, the fish were placed in a white compartment, after 30 s the door was opened. When the fish crossed to a black compartment, a weight was dropped (aversive stimuli). Immediately after the third trial, on training days, the fish received, intraperitoneally, one of the pharmacological treatments (saline (N = 20), 8 (N = 12) or 16 (N = 13) µg/g chlorpheniramine, CPA). On the test day, the time to cross to the black compartment was determined. The latency of the saline group increased significantly only on the 3rd trial of the 2nd training day (mean ± SEM, T1 (50.40 ± 11.69), 2T3 (226.05 ± 25.01); ANOVA: P = 0.0249, Dunn test: P < 0.05). The group that received 8 µg/g CPA showed increased latencies from the 2nd training day until the test day (T1 (53.08 ± 17.17), 2T2 (197.75 ± 35.02), test (220.08 ± 30.98); ANOVA: P = 0.0022, Dunn test: P < 0.05)). These results indicate that CPA had a facilitating effect on memory. We suggest that the fish submitted to telencephalic ablation were able to learn due to the local circuits of the mesencephalon and/or diencephalon and that CPA interferes in these circuits, probably due an anxiolytic-like effect.

show abstract

supporting

confidence: 91%

Chlorpheniramine facilitates inhibitory avoidance in teleosts submitted to telencephalic ablation

Faganello

Mattioli

2008

Braz J Med Biol Res

View full text Add to dashboard Cite

show abstract

“…These changes are characteristic of neuronal activation along the defense pathway, which can produce autonomic, cardiovascular, nociceptive, and behavioral elements related to stress, anxiety, panic, and fear (1,4,8,9,16,19). Sympathoexcitation and an increase in arterial blood pressure are key components of acute stress, as exemplified by the defense response and are coordinated in the dorsal PAG (4,14,20,23). Increases in sympathetic nerve activity and blood pressure mediated by excitatory amino acid transmission in the dPAG are refined by neuromodulators to shape the final output response.…”

Section: Discussionmentioning

confidence: 99%

Cannabinoid and GABA modulation of sympathetic nerve activity and blood pressure in the dorsal periaqueductal gray of the rat

Dean

2011

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Sympathoexcitation and increased blood pressure evoked by central networks integrating defensive behavior are fundamental to the acute stress response. A balance between excitatory glutamatergic and inhibitory GABAergic neurotransmission in the dorsal periaqueductal gray (dPAG) results in a tonic level of activity in the alerting system. Neuromodulators such as endocannabinoids have been shown to influence the sympathoexcitatory and pressor components of acute stress in the dPAG, exemplified by the defense response as a model, but the mechanism of integration remains unknown. The present study examines the role of GABA and its interaction with endocannabinoids in modulating sympathetic nerve activity and blood pressure related to the defense response. Microinjection of the broad-spectrum excitatory amino acid dl-homocysteic acid (DLH) identified sites of the defense pathway in the dPAG from which an increase in renal sympathetic nerve activity and blood pressure could be evoked, and subsequent microinjections were made at the same site through a multibarrelled micropipette. Blockade of GABAA receptors or microinjection of the cannabinoid 1 receptor agonist anandamide elicited a renal sympathoexcitation and pressor response. Prior microinjection of the GABAA receptor antagonist gabazine attenuated the sympathoexcitation and pressor response associated with anandamide microinjection. In contrast, the sympathetic response to DLH was enhanced by GABAA receptor blockade. These data demonstrate that sympathoexcitatory neurons in the dPAG are under tonic inhibition by GABA and that endocannabinoids modulate this GABAergic neurotransmission to help regulate components of the defense response.

show abstract

“…Among the motor reactivities involved in the deep SC/ DpMe are defensive reactions (Dean et al, 1988;Redgrave et al, 1996;Niemi-Junkola et al, 1997;Brandao et al, 2003), startle response modulation (Meloni and Davis, 2000), convulsions (Garcia-Rill et al, 1985;Hashizume et al, 2000;Ishimoto et al, 2000), and locomotor activity (Sinnamon and Stopford, 1987;Sinnamon, 1993;Jordan, 1998). The specificity of NBQX infused into this area on fear-potentiated startle compared with baseline startle suggests that amygdala terminals may release glutamate into the deep SC/DpMe when activated by a CS.…”

Section: Discussionmentioning

confidence: 99%

Fear-Potentiated Startle in Rats Is Mediated by Neurons in the Deep Layers of the Superior Colliculus/Deep Mesencephalic Nucleus of the Rostral Midbrain through the Glutamate Non-NMDA Receptors

Zhao¹,

Davis²

2004

J. Neurosci.

View full text Add to dashboard Cite

The amygdala sends heavy and broad projections to the rostral midbrain including the periaqueductal gray (PAG), the deep layers of the superior colliculus/deep mesencephalic nucleus (deep SC/DpMe), and the lateral mesencephalic reticular formation (MRF) that in turn project to the nucleus reticularis pontis caudalis (PnC), an obligatory relay in the primary acoustic startle circuit. Chemical lesions or inactivation of these areas blocked fear-potentiated startle, suggesting that these areas serve as a relay between the amygdala and the PnC. In the present study, we tried to determine more precisely which of these sites were critical for fear-potentiated startle and the role of glutamate receptors in this site in mediating fear-potentiated startle. Local infusion of the non-NMDA receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(F)-quinoxaline (NBQX) dose-dependently blocked fear-potentiated startle when infused into the deep SC/ DpMe before testing but had no effect on baseline startle amplitude. NBQX did not block fear-potentiated startle when infused before training. The same dose of NBQX infused into the dorsal/lateral PAG, the lateral MRF, or the superficial layers of the SC did not affect fear-potentiated startle. However, NBQX tended to reduce contextual freezing when infused into the dorsal/lateral PAG. These findings suggest that the deep SC/DpMe is the site that serves as a critical output relay between the amygdala and the PnC in mediating fearpotentiated startle and that glutamatergic transmission is required for this action.

show abstract

The relevance of neuronal substrates of defense in the midbrain tectum to anxiety and stress: empirical and conceptual considerations

Cited by 145 publications

References 92 publications

Chlorpheniramine facilitates inhibitory avoidance in teleosts submitted to telencephalic ablation

Chlorpheniramine facilitates inhibitory avoidance in teleosts submitted to telencephalic ablation

Cannabinoid and GABA modulation of sympathetic nerve activity and blood pressure in the dorsal periaqueductal gray of the rat

Fear-Potentiated Startle in Rats Is Mediated by Neurons in the Deep Layers of the Superior Colliculus/Deep Mesencephalic Nucleus of the Rostral Midbrain through the Glutamate Non-NMDA Receptors

Contact Info

Product

Resources

About