| Full text | |
| Author(s): Show less - |
Osaki, M. Y.
;
Castellan-Baldan, L.
[2]
;
Calvo, F.
[3]
;
Carvalho, A. D.
;
Felippotti, T. T.
;
Oliveira, R. de
;
Ubiali, W. A.
[7]
;
Paschoalin-Maurin, T.
;
Elias-Filho, D. H.
[9]
;
Motta, V.
;
et al.
Total Authors: 11
|
| Document type: | Journal article |
| Source: | Brain Research; v. 992, n. 2, p. 179-192, Dec. 2003. |
| Field of knowledge: | Biological Sciences - Pharmacology |
| Abstract | |
Deep layers of the superior colliculus (DLSC), the dorsal and ventral periaqueductal gray matter (PAG), and inferior colliculus (IC) are midbrain structures involved in the generation of defensive behavior. β-Endorphin and Leu-enkephalin are some neurotransmitters that may modulate such behavior in mammals. Light microscopy immunocytochemistry with streptavidin method was used for the localization of the putative cells of defensive behavior with antibodies for endogenous opioids in rat brainstem. Midbrain structures showed positive neurons to β-endorphin and Leu-enkephalin in similar distributions in the experimental animals, but we also noted the presence of varicose fibers positive to endogenous opioids in the PAG. Neuroanatomical techniques showed varicose fibers from the central nucleus of the inferior colliculus to ventral aspects of the PAG, at more caudal levels. Naloxonazine and nor-binaltorphimine, competitive antagonists that block μ1- and κ-opioid receptors, were then used in the present work to investigate the involvement of opioid peptide neural system in the control of the fear-induced reactions evoked by electrical stimulation of the neural substrates of the inferior colliculus. The fear-like responses were measured by electrical stimulation of the central nucleus of the inferior colliculus, eliciting the escape behavior, which is characterized by vigorous running and jumping. Central administration of opioid antagonists (2.5 μg/0.2 μl and 5.0 μg/0.2 μl) was performed in non-anesthetized animals (Rattus norvegicus), and the behavioral manifestations of fear were registered after 10 min, 2 h, and 24 h of the pretreatment. Naloxonazine caused an increase of the defensive threshold, as compared to control, suggesting an antiaversive effect of the antagonism on μ1-opioid receptor. This finding was corroborated with central administration of nor-binaltorphimine, which also induced a decrease of the fear-like responses evoked by electrical stimulation of the inferior colliculus, since the threshold of the escape behavior was increased 2 and 24 h after the blockade of κ-opioid receptor. These results indicate that endogenous opioids may be involved in the modulation of fear in the central nucleus of the inferior colliculus. Although the acute treatment (after 10 min) of both naloxonazine and nor-binaltorphimine causes nonspecific effect on opioid receptors, we must consider the involvement of μ1- and κ-opioid receptors in the antiaversive influence of the opioidergic interneurons in the dorsal mesencephalon, at caudal level, after chronic (2–24 h) treatment of these opioid antagonists. The neuroanatomical study of the connections between the central nucleus of the inferior colliculus and the periaqueductal gray matter showed neuronal fibers with varicosities and with terminal bottons, both in the pericentral nucleus of the inferior colliculus and in ventral and dorsal parts of caudal aspects of the periaqueductal gray matter. (AU) | |
| FAPESP's process: | 02/01496-5 - Estudo do envolvimento do núcleo magno da rafe, do núcleo gigantocelular e núcleo pré-tectal anterior, e de receptores opióides, mu, kappa e delta serotininérgicos 5-HT2A/2C e noradrenérgicos alfa e beta na analgesia pós-ictal: um estudo neuroanatômico e neuropsicofisiológico em um modelo experimental de epilepsia |
| Grantee: | Norberto Cysne Coimbra |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 02/05337-9 - Estudo neuromorfológico e psicofisiológico do duplo elo gabaérgico estriado-nigrotectal e de sua influência sobre o comportamento de defesa eliciado por estimulação do colículo inferior |
| Grantee: | Lissandra Castellan Baldan |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 02/01497-1 - Estudo do envolvimento do núcleo magno da rafe, do núcleo gigantocelular e núcleo pré-tectal anterior, e de receptores opiódes, kappa e delta serotoninérgicos 5HT2/1C, e noradrenérgicos alfa, beta, na analgesia pós-cital: um estudo neuroanatômico e neuropsicofisiológico em um modelo experimental de epilepsia |
| Grantee: | Daoud Hibrahim Elias Filho |
| Support Opportunities: | Scholarships in Brazil - Technical Training Program - Technical Training |
| FAPESP's process: | 95/08418-4 - Estudo da neuroquímica de processos aversivos e antinociceptivos em estruturas encefálicas, utilizando microeletrodos na determinação de neurotransmissores in vitro e in vivo através das técnicas de (... ) |
| Grantee: | Luis Antonio da Silva |
| Support Opportunities: | Research Grants - Young Investigators Grants |
| FAPESP's process: | 00/08953-7 - Estudo neuroanatomico e psicofarmacologico do duplo elo gabaergico estriado-nigro-tectal e de sua influencia sobre o comportamento de defesa eliciado por estimulacao do coliculo inferior. |
| Grantee: | Lissandra Castellan Baldan |
| Support Opportunities: | Scholarships in Brazil - Master |
| FAPESP's process: | 96/06946-6 - Estudo da neuroquímica de processos aversivos e antinoceptivos em estruturas encefálicas, utilizando microeletrodos na determinação de neurotransmissores in vitro e in vivo através de voltametria cíclica e de pulso diferencial |
| Grantee: | Luis Antonio da Silva |
| Support Opportunities: | Scholarships in Brazil - Young Researchers |
| FAPESP's process: | 98/11187-2 - Neurobiology of fear and stress |
| Grantee: | Marcus Lira Brandão |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 96/08574-9 - Estudo de processos antinociceptivos pos-ictais em modelos experimentais de epilepsia. |
| Grantee: | Norberto Cysne Coimbra |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 97/11097-0 - Aquisição de equipamentos e material de consumo para imuno-localização ultraestrutural de proteínas solúveis |
| Grantee: | Antonio Haddad |
| Support Opportunities: | Research Infrastructure program - Equipment |
| FAPESP's process: | 03/03118-0 - Estudo neuroanatômico funcional e neurofarmacológico do envolvimento do núcleo pre-tectal anterior e estruturas funcionalmente relacionadas em processos antinociceptivos |
| Grantee: | Andressa Daiane de Carvalho Zaparolli |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 02/03705-0 - Neurobiology of fear and stress |
| Grantee: | Marcus Lira Brandão |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 02/13307-2 - Estudo da interação entre mecanismos opióides e GABAérgicos na modulação do comportamento de defesa eliciado por estimulação elétrica e química do colículo inferior de Rattus norvegicus |
| Grantee: | Fabricio Calvo |
| Support Opportunities: | Scholarships in Brazil - Master |
| FAPESP's process: | 03/01768-8 - Estudo neuromorfológico, neurofarmacológico e neuroetológico das respostas induzidas pelo medo e do efeito de drogas antipânico sobre o comportamento defensivo de Mesocricetus auratus em contato agressivo com Crotalus durissus terrificus (Reptilia, Viperidae) |
| Grantee: | Walter Adriano Ubiali |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |