Summary
The GABAergic modulation in the nucleus accumbens septi (NAS) of muscle tone was investigated in rats using behavioral tests. The GABAB receptor agonist baclofen dose-dependently decreased muscle tone in the wiremesh and bar holding tests both after local injection into the NAS (1.0 and 2.5 μg), and after intraperitoneal administration in a dose of 20 mg/kg. In the Wirth's test haloperidol (5 mg/kg i.p.), produced catalepsy, whereas baclofen (20 mg/kg, i.p.) significantly deteriorated rats' performance. Intraaccumbens microinjections of muscimol, midazolam, nicardipine, as well as peripheral injections of haloperidol and midazolam failed to modify muscle tone in the wire-mesh test. These findings argue against the involvement of GABAA receptors, benzodiazepine receptors, as well as dopaminergic- and calcium channel-related mechanisms in the effect of baclofen. Hence, the muscle relaxant effect of baclofen seems to be also mediated through GABAB receptor sites within the NAS.
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Stefański, R., Plaznik, A., Pałejko, W. et al. Myorelaxant effect of baclofen injected to the nucleus accumbens septi. J Neural Transm Gen Sect 2, 179–191 (1990). https://doi.org/10.1007/BF02257649
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DOI: https://doi.org/10.1007/BF02257649