Functional and ultrastructural neuroanatomy of interactive intratectal/tectonigral mesencephalic opioid inhibitory links and nigrotectal GABAergic pathways: Involvement of GABAA and μ1-opioid receptors in the modulation of panic-like reactions elicited by electrical stimulation of the dorsal midbrain

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

“…In addition, interaction between endogenous opioid peptides and endocannabinoids has already been demonstrated (Manzanares et al, 1999). There is also morphological and neuropharmacological evidence that the mesencephalic tectum is also connected to the reticulate division of the substantia nigra (Ribeiro et al, 2005;da Silva et al, 2013), a ventral mesencephalic structure rich in CB 1 cannabinoid receptors (Matsuda et al, 1990). Additionally, pharmacological interactions between CBD and serotoninergic receptors in mesencephalic and prosencephalic structures of the brain aversion system have been recently reported, which may also explain the effects observed in the present study (Campos and Guimarães, 2008;Resstel et al, 2009).…”

“…Recently, such defensive responses triggered by stimulation of the dorsal midbrain (Nashold et al, 1969;Ribeiro et al, 2005;CastellanBaldan et al, 2006) have also been elicited by the stimulation of medial hypothalamus (Freitas et al, 2009;Wilent et al, 2010;Biagioni et al, 2012Biagioni et al, , 2013de Freitas et al, 2014), although escape behaviour elaborated by hypothalamic neurons are preceded by more intense exploratory behaviour (Schmitt et al, 1985). Interestingly, the escape responses organised by medial hypothalamus nuclei are mainly expressed by vertical jumps, toward the top of the aversive environment (de Freitas et al, 2014) instead of horizontal (long jumps) which is elicited by superior colliculus strata, as seen in the present work.…”

“…In fact, there is evidence suggesting a role played by endogenous opioid peptidemediated system in the modulation of panic-like responses organised by dorsal midbrain structures (Eichenberger et al, 2002;Ribeiro et al, 2005;Castellan-Baldan et al, 2006;Twardowschy and Coimbra, 2015). In addition, interaction between endogenous opioid peptides and endocannabinoids has already been demonstrated (Manzanares et al, 1999).…”

“…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

“…Grandes avanços na compreensão desses transtornos vêm sendo obtidos através de estudos com estimulação elétrica (COIMBRA et al, 1998;EICHENBERGER et al, 2002;OSAKI et al, 2003;RIBEIRO et al, 2005;) e química (BRANDÃO et al, 1988;CARDOSO et al, 1994;EICHENBERGER et al, 2002) de determinadas estruturas encefálicas.…”