The central hypotensive action of baclofen in the anaesthetized cat.
In the pentobarbital-anaesthetized cat, the intracerebroventricular administration of 20 microgram/kg d,1-baclofen led to marked hypotension and bradycardia, whereas the same dose of d-baclofen (i.c.v.) had no cardiovascular effect. When the drug was prevented from reaching the brain stem structures by collecting perfusate through a catheter lodged in the Aqueduct of Sylvius, the efficacy of d,1-baclofen was increased. Bicuculline did not antagonize the central cardiovascular effects of d,1-baclofen at doses which inhibit the cardiovascular effects of GABA agonists. However, both glutamic acid and kainic acid prevented and reversed the central hypotension and bradycardia produced by d,1-baclofen. These effects of baclofen may therefore be mediated by a selective inhibition of the release of the excitatory neurotransmitter, glutamate, within forebrain structures involved in central cardiovascular regulation.
D000758:Anesthesia; D000818:Animals; D001418:Baclofen / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D002415:Cats; D005260:Female; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D006339:Heart Rate / Q000187:drug effects; D007608:Kainic Acid / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000187:drug effects; D011963:Receptors, GABA-A
D005971:Glutamates; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D018698:Glutamic Acid; D001418:Baclofen; D007608:Kainic Acid