title: Theophylline-induced grooming: possible indirect dopaminergic mechanism.
abstract: The ability of theophylline, an adenosine antagonist and phosphodiesterase inhibitor, to induce grooming was studied in rats. Grooming was induced by intraperitoneal (i.p.) injection of different doses (6-25 mg/kg) of theophylline to rats. The effect was dose-dependent. However, the response was decreased with increasing doses of the drug from 25-75 mg/kg. Administration of the dopamine D1 receptor agonist SKF 38393 (1-phenyl-7,8-dihydroxy-2,3,4,5-tetrahydro-1 H-3-benzazepine hydrochloride; 16 mg/kg i.p.) also caused grooming in a dose-dependent manner. The response induced by SKF 38393 (1-4 mg/kg i.p.) was decreased by the high doses of theophylline (50 and 75 mg/kg i.p.). The dopamine D1 receptor antagonist SCH 23390 (R-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1 H-benzazepine-7-ol maleate) decreased the theophylline and SKF 38393 response. Pretreatment of animals with reserpine (2.5 mg/kg i.p., 24 h) reduced the effect of theophylline (12.5 and 25 mg/kg i.p.) but not that of SKF 38393 (1 and 4 mg/kg i.p.). It is concluded that theophylline elicits grooming through an indirect D1 dopaminergic mechanism.
authors.affiliation: Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Iran.
authors.forename: M R
authors.initials: MR
authors.lastname: Zarrindast
authors.forename: M
authors.initials: M
authors.lastname: Sharifzadeh
authors.forename: A I
authors.initials: AI
authors.lastname: Sadeghi
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006120:Grooming / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D051381:Rats; D012110:Reserpine / Q000494:pharmacology; D013806:Theophylline / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D018759:Adrenergic Uptake Inhibitors; D001552:Benzazepines; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D010726:Phosphodiesterase Inhibitors; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D012110:Reserpine; D013806:Theophylline