Intracerebral injection of R-(-)-Apomorphine into the nucleus accumbens decreased carbachol-induced 22-kHz ultrasonic vocalizations in rats

Autor: Michael Silkstone, Stefan M. Brudzynski
Rok vydání: 2019
Předmět:
Zdroj: Behavioural Brain Research. 364:264-273
ISSN: 0166-4328
DOI: 10.1016/j.bbr.2019.01.044
Popis: Rats can produce ultrasonic vocalizations (USVs) in a variety of different contexts that signal their emotional state to conspecifics. Under distress, rats can emit 22-kHz USVs, while during positive pro-social interactions rats can emit frequency-modulated (FM) 50-kHz USVs. It has been previously reported that rats with increasing emission of FM 50-kHz USVs in anticipation of rewarding electrical stimulation or positive pro-social interaction decrease the number of emitted 22-kHz USVs. The purpose of the present investigation was to determine, in a pharmacological-behavioural experiment, if the positive emotional arousal of the rat indexed by the number of emitted FM 50-kHz USVs can decrease the magnitude of a subsequent negative emotional state indexed by the emission of 22-kHz USVs. To induce a positive emotional state, an intracerebral injection of a known D 1/D2 agonist R-(-)-apomorphine (3.0 μg/0.3 μl) into the medial nucleus accumbens shell was used, while a negative emotional state was induced by intracerebral injection of carbachol (1.0 μg/0.3 μl), a known broad-spectrum muscarinic agonist , into the anterior hypothalamic-medial preoptic area . Our results demonstrated that initiation of a positive emotional state was able to significantly decrease the magnitude of subsequently expressed negative emotional state measured by the number of emitted 22-kHz USVs. The results suggest the neurobiological substrates that initiate positive emotional state indirectly antagonize the brain regions that initiate negative emotional states.
Databáze: OpenAIRE
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