title: Myorelaxant effect of baclofen injected to the nucleus accumbens septi.
abstract: 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.
authors: Department of Pharmacology and Physiology of the Nervous System, Institute of Psychiatry and Neurology, Warsaw, Poland.
authors: R
authors: R
authors: Stefański
authors: A
authors: A
authors: Plaznik
authors: W
authors: W
authors: Pałejko
authors: W
authors: W
authors: Kostowski
mesh_terms: D000818:Animals; D001418:Baclofen / Q000008:administration & dosage / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006220:Haloperidol / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D008297:Male; D008845:Microinjections; D008874:Midazolam / Q000494:pharmacology; D009118:Muscimol / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects*; D009529:Nicardipine / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013647:Task Performance and Analysis; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D009529:Nicardipine; D001418:Baclofen; D006220:Haloperidol; D008874:Midazolam