Article date: 1990/1/1
PubMed ID: 2257059
Journal name: Journal of neural transmission. Parkinson's disease and dementia section (ISSN: 0936-3076)
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 wire-mesh and bar holding tests both after local injection into the NAS (1.0 and 2.5 micrograms), 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.
Author List: Stefański R, Plaznik A, Pałejko W, Kostowski W
Publication Types: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't
Substances mentioned in the article: Muscimol; gamma-Aminobutyric Acid; Nicardipine; Baclofen; Haloperidol; Midazolam;
Mesh terms: Animals; Baclofen/administration & dosage; Behavior, Animal/drug effects; Dose-Response Relationship, Drug; Haloperidol/pharmacology; Injections, Intraperitoneal; Male; Microinjections; Midazolam/pharmacology; Muscimol/pharmacology; Muscle Relaxation/drug effects; Nicardipine/pharmacology; Nucleus Accumbens/drug effects; Rats; Rats, Inbred Strains; Task Performance and Analysis; gamma-Aminobutyric Acid/pharmacology;