Opposing roles of dorsomedial hypothalamic CB1 and TRPV1 receptors in anandamide signaling during the panic-like response elicited in mice by Brazilian rainbow Boidae snakes
- 53 Downloads
The endocannabinoid system plays an important role in the organization of panic-like defensive behavior. Threatening situations stimulate brain areas, such as the dorsomedial hypothalamus (DMH). However, there is a lack of studies addressing the role of the DMH endocannabinoid system in panic-like responses.
We aimed to verify which mechanisms underlie anandamide-mediated responses in the DMH.
To test the hypothesis that the anandamide produces panicolytic-like effects, we treated mice with intra-DMH microinjections of vehicle or increasing doses of anandamide (0.5, 5, or 50 pmol) and then performed confrontation with the South American snake Epicrates cenchria assisi.
Intra-DMH anandamide treatment yielded a U-shaped dose-response curve with no effect of the lowest (0.5 pmol) or the highest (50 pmol) dose and significant inhibition of panic-like responses at the intermediate (5 pmol) dose. In addition, this panicolytic-like effect was prevented by pretreatment of the DMH with the CB1 receptor antagonist AM251 (100 pmol). However, pretreatment of the DMH with the TRPV1 receptor antagonist 6-iodo-nordihydrocapsaicin (3 nmol) restored the panicolytic-like effect of the highest dose of anandamide. Immunohistochemistry revealed that CB1 receptors were present primarily on axonal fibers, while TRPV1 receptors were found almost exclusively surrounding the perikarya in DMH.
The present results suggest that anandamide exerts a panicolytic-like effect in the DMH by activation of CB1 receptors and that TRPV1 receptors are related to the lack of effect of the highest dose of anandamide.
KeywordsDorsomedial hypothalamus Defensive behavior Anandamide CB1 cannabinoid receptor TRPV1 channel
The authors would like to thank Daoud Hibrahim Elias Filho for expert technical assistance with the immunohistochemistry procedure. D.H. Elias-Filhos was the recipient of technician scholarships from FAPESP (TT-2, grant 02/01497-1) and CNPq (grant 372838/2018-9).
This work was supported by the Conselho Nacional de Pesquisa e Desenvolvimento Tecnológico (CNPq) (grants 470119/2004-7 and 427397/2018-9)), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (grants 2012/03798-0, 2017/11855-8), and a Pro-Rectory of the University of São Paulo (USP) research grant (NAP-USP-NuPNE; grant IaPq2012-156-USP-12.1.25440.01.6). T. dos Anjos-Garcia was financially supported by CNPq (Scientiae Doctor Fellowship, grant 141124/2014-8) and is a postdoctorate researcher supported by FAPESP (grant 2917/22647-7). None of the organizations played further roles in the study design; the collection, analysis, or interpretation of the data; the writing of the report; or the decision to submit the paper for publication. N.C. Coimbra is a researcher (level 1A) from CNPq (grant 301341/2015-0).
Compliance with ethical standards
The experimental procedures were approved by the Commission of Ethics in Animal Experimentation (CONCEA process 227/2014) of the Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP).
Conflict of interest
The authors declare that they have no conflicts of interest.
- Almada RC, Coimbra NC (2015) Recruitment of striatonigral disinhibitory and nigrotectal inhibitory GABAergic pathways during the organization of defensive behavior by mice in a dangerous environment with the venomous snake Bothrops alternatus (Reptilia, Viperidae). Synapse 69:299–313Google Scholar
- Almada RC, Roncon CM, Elias-Filho DH, Coimbra NC (2015) Endocannabinoid signaling mechanisms in the substantia nigra pars reticulata modulate GABAergic nigrotectal pathways in mice threatened by urutu-cruzeiro venomous pit viper. Neuroscience 303:503–514Google Scholar
- Biagioni AF, de Oliveira RC, de Oliveira R, da Silva JA, dos Anjos-Garcia T, Roncon CM, Corrado AP, Zangrossi HJ, Coimbra NC (2016a) 5-Hydroxytryptamine 1A receptors in the dorsomedial hypothalamus connected to dorsal raphe nucleus inputs modulate defensive behaviours and mediate innate fear-induced antinociception. Eur Neuropsychopharmacol 26:532–545CrossRefGoogle Scholar
- Biagioni AF, dos Anjos-Garcia T, Ullah F, Fisher IR, Falconi-Sobrinho LL, de Freitas RL, Felippotti TT, Coimbra NC (2016b) Neuroethological validation of an experimental apparatus to evaluate oriented and non-oriented escape behaviours: comparison between the polygonal arena with a burrow and the circular enclosure of an open-field test. Behav Brain Res 298(Part B):65–77CrossRefGoogle Scholar
- Calvo F, Lobão-Soares B, de Freitas RL, Paschoalin-Maurin T, dos Anjos-Garcia T, Medeiros P, da Silva JA, Lovick TA, Coimbra NC (2019) The endogenous opioid system modulates defensive behavior evoked by Crotalus durissus terrificus: panicolytic-like effect of intracollicular non-selective opioid receptors blockade. J Psychopharmacol 33:51–61Google Scholar
- Casarotto PC, Terzian ALB, Aguiar DC, Zangrossi H, Guimarães FS, Wotjak CT, Moreira FA (2012) Opposing roles for cannabinoid receptor type-1 (CB1) and transient receptor potential vanilloid type-1 channel (TRPV1) on the modulation of panic-like responses in rats. Neuropsychopharmacology 37:478–486CrossRefGoogle Scholar
- Coimbra NC, Paschoalin-Maurin T, Bassi GS, Kanashiro A, Biagioni AF, Felippotti TT, Elias-Filho DH, Mendes-Gomes J, Cysne-Coimbra JP, Almada RC, Lobão-Soares B (2017) Critical neuropsychobiological analysis of panic attack- and anticipatory anxiety-like behaviors in rodents confronted with snakes in polygonal arenas and complex labyrinths: a comparison to the elevated plus- and T-maze behavioral tests. Braz J Psychiatr 39:72–83CrossRefGoogle Scholar
- dos Anjos-Garcia T, Ullah F, Falconi-Sobrinho LL, Coimbra NC (2017) CB1 cannabinoid receptor-mediated anandamide signalling reduces the defensive behaviour evoked through GABAA receptor blockade in the dorsomedial division of the ventromedial hypothalamus. Neuropharmacology 113(Part A):156–166CrossRefGoogle Scholar
- Paschoalin-Maurin T, dos Anjos-Garcia T, Falconi-Sobrinho LL, de Freitas RL, Coimbra JPC, Laure CJ, Coimbra NC (2018) The rodent-versus-wild snake paradigm as a model for studying anxiety- and panic-like behaviors: face, construct and predictive validities. Neuroscience 369:336–349CrossRefGoogle Scholar
- Paxinos G, Franklin KBJ (2001) The mouse brain in stereotaxic coordinates. Academic Press, San DiegoGoogle Scholar
- Ullah F, dos Anjos-Garcia T, dos Santos IR, Biagioni AF, Coimbra NC (2015) 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. Behav Brain Res 293:143–152CrossRefGoogle Scholar
- Ullah F, dos Anjos-Garcia T, Mendes-Gomes J, Elias-Filho DH, Falconi-Sobrinho LL, de Freitas RL, Khan AU, Oliveira R, Coimbra NC (2017) Connexions between the dorsomedial division of the ventromedial hypothalamus and the dorsal periaqueductal grey matter are critical in the elaboration of hypothalamically mediated panic-like behaviour. Behav Brain Res 319:135–147CrossRefGoogle Scholar
- Uribe-Mariño A, Francisco A, Castiblanco-Urbina MA, Twardowschy A, Salgado-Rohner CJ, Crippa JAS, Hallak JEC, Zuardi AW, Coimbra NC (2012) Anti-aversive effects of cannabidiol on innate fear-induced behaviors evoked by an ethological model of panic attacks based on a prey vs the wild snake Epicrates cenchria crassus confrontation paradigm. Neuropsychopharmacology 37:412–421CrossRefGoogle Scholar