title: Antagonists of adenosine and alpha-2-adrenoceptors reverse the anticonvulsant effects of tizanidine in DBA/2 mice.
abstract: The anticonvulsant activity of 5-chloro-4-(2-imidazolin-2yl-amino)-2,1,3-benzothiazole, tizanidine, was studied following intraperitoneal (i.p.) administration in DBA/2 mice (which show sound-induced seizures). Protection against sound-induced seizures was observed after tizanidine, (0.5-4 mg/kg i.p.). The ED50 values for suppression of the tonic, clonic and wild running phases of sound-induced seizures were 0.54, 0.76 and 1.43 mg/kg, respectively. This protective action was significantly reduced by pretreatment with aminophylline (25 mg/kg i.p.), yohimbine (1 mg/kg i.p.) or piperoxan (20 mg/kg i.p.). Methysergide, a serotonin antagonists, did not significantly reduce the anticonvulsant effects of tizanidine. The present experiments suggest an involvement of purinergic and adrenergic mechanisms in the anticonvulsant action of tizanidine.
authors.affiliation: Institute of Pharmacology, University of Reggio Calabria, Italy.
authors.forename: G B
authors.initials: GB
authors.lastname: De Sarro
authors.forename: A
authors.initials: A
authors.lastname: De Sarro
mesh_terms: D000241:Adenosine / Q000037:antagonists & inhibitors*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000628:Aminophylline / Q000494:pharmacology; D000818:Animals; D000927:Anticonvulsants / Q000037:antagonists & inhibitors*; D003000:Clonidine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D008784:Methysergide / Q000494:pharmacology; D051379:Mice; D008811:Mice, Inbred DBA; D010883:Piperoxan / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000317:Adrenergic alpha-Antagonists; D000927:Anticonvulsants; D000628:Aminophylline; D015016:Yohimbine; C023754:tizanidine; D010883:Piperoxan; D000241:Adenosine; D003000:Clonidine; D008784:Methysergide