Neuroanatomical approaches of the tectum-reticular pathways and immunohistochemical evidence for serotonin-positive perikarya on neuronal substrates of the superior colliculus and periaqueductal gray matter involved in the elaboration of the defensive behavior and fear-induced analgesia

Relevance of dorsomedial hypothalamus, dorsomedial division of the ventromedial hypothalamus and the dorsal periaqueductal gray matter in the organization of freezing or oriented and non-oriented escape emotional behaviors

“…Considering dPAG, one-way ANOVA showed significant effect of treatment in the frequency (F (3,27) > 4.51; p < 0.05 in all cases) of tail twitching, frequency (p < 0.001) and duration (p < 0.001) of freezing, frequency (p < 0.001) and duration (p < 0.001) of alertness, frequency (p < 0.001) and duration (p < 0.001) of explosive escape, frequency (p < 0.001) of horizontal jumps, frequency (p < 0.01) and duration (p < 0.01) of oriented escape to the burrow, and frequency (p < 0.001) of crossing.…”

“…Nashold et al reported for the first time in humans that the electrical stimulation of the dorsal periaqueductal gray matter (dPAG) and other midbrain tectum structures produce autonomic changes and feelings of fear that are the symptoms of panic attacks [2]. Later on, the prior findings were confirmed in animal model by electrically stimulating dPAG that induced explosive escape responses [3,4]. Additionally, pharmacological studies also confirmed that dPAG is an important structure that has a role in organizing defensive behaviors [5,6].…”

Dissociation between the panicolytic effect of cannabidiol microinjected into the substantia nigra, pars reticulata, and fear-induced antinociception elicited by bicuculline administration in deep layers of the superior colliculus: The role of CB1-cannabinoid receptor in the ventral mesencephalon

“…Fear-induced antinociception has also been considered a part of defensive behaviour (Fanselow and Bolles, 1979;Coimbra et al, 2006). In fact, without the existence of a neural system for inhibiting nociceptive impulses, animals confronted with a natural predator would elicit recovery behaviour induced by pain instead of fear-induced defensive behaviour, reflecting their vulnerability to future injury and death.…”

“…The γ-aminobutyric acid-A (GABA A ) receptor is involved in the modulation of innate fear-induced behaviour organised by the periaqueductal grey matter (PAG) and deep layers of the superior colliculus (dlSC) (Coimbra and Brandão, 1993;Coimbra et al, 2006). At least part of the neural substrates involved in the control of panic-like responses includes the neostriatum-nigral disinhibitory and nigro-collicular inhibitory GABAergic neural pathways (Coimbra and Brandão, 1993;Ribeiro et al, 2005;Castellan-Baldan et al, 2006).…”

Envolvimento de vias mediadas por endocanabinoides na modulação do comportamento de defesa induzido pelo bloqueio de receptores GABAA na divisão dorso-medial do hipotálamo ventro-medial: papel do receptor CB1

“…Tais dados supracitados são condizentes com os descritos em estudos com estimulação elétrica e química de estruturas prosencefálicas e mesencefálicas (COIMBRA et al, 2006;de FREITAS et al, 2013a,b;FREITAS et al, 2009;GRAEFF et al, 1986a,b), assemelhando-se muito a padrões comportamentais observados em animais expostos a ameaças naturais. SCHMITT; KARLI, 1984;BRANDÃO et al, 1986;MILANI;GRAEFF, 1987;SILVEIRA;GRAEDD, 1992;de FREITAS et al, 2013a,b;FREITAS et al, 2009) MARTIN, 1995;SCHENBERG et al, 2001).…”