Mu-opioid receptors in septum mediate the development of behavioural sensitization to a single morphine exposure in male rats.
Addict Biol
; 27(1): e13066, 2022 01.
Article
em En
| MEDLINE
| ID: mdl-34030217
ABSTRACT
Behavioural sensitization (BS) is characterized by enhanced psychomotor responses to a dose of substance of abuse after prior repeated exposure. We previously reported that BS can be induced by a single injection of morphine in rats, whereas septal nuclei are specifically involved in the development phase of BS. Here, we demonstrated that intra-LS or intra-MS microinjections also incubated BS to a systemic morphine injection in a cross-sensitization fashion, whereas inactivation of either subdivision of septal nuclei (LS lateral septum; MS medial septum) can negate this ability of morphine. Then, non-selective (naloxone) and selective (µ-, δ- and κ-)opioid receptor antagonists were directly delivered into LS or MS, respectively, ahead of a morphine microinjection, whereas only µ-opioid receptors in both LS and MS play indispensable roles in mediating the BS development. Finally, there was a pronounced elevation in the levels of the monoamines (i.e. dopamine, homovanillic acid, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid) in the septum, 8 h after a morphine injection detected with a HPLC-ECD method, suggesting that dopaminergi and serotoninergic systems are implicated in the BS formation. Our studies demonstrated that septal nuclei critically participate in the BS development. Essentially, µ- instead of δ- or κ-opioid receptors in LS and MS mediate sensitization to opiates.
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Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Núcleos Septais
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Receptores Opioides mu
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Morfina
Limite:
Animals
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article