title: Effects of nifedipine and Bay K 8644 on the R-PIA and caffeine-induced changes in the locomotor activity of rats.
abstract: Possible interaction between adenosine and L type Ca2+ channel in the locomotor activity of rats was investigated. R-PIA (0.05 mg kg-1), an adenosine analogue, and caffeine (20 mg kg-1), an adenosine receptor antagonist, significantly decreased and increased locomotor activity, respectively. Ca2+ channel blocker nifedipine (5 mg kg-1) and the channel activator Bay K 8644 (0.5 mg kg-1) did not alter the locomotor activity. However, both drugs significantly potentiated the inhibitory effect of R-PIA on the locomotor activity. Additionally, caffeine induced increase in the locomotor activity was significantly blocked by nifedipine and Bay K 8644. This interaction might be due to the inhibitory effects of nifedipine and Bay K 8644 on the uptake of adenosine by rat brain.
authors.affiliation: Istanbul University, Istanbul Medical Faculty, Department of Pharmacology and Clinical Pharmacology, Capa, Turkey.
authors.forename: L
authors.initials: L
authors.lastname: Eroglu
authors.forename: R
authors.initials: R
authors.lastname: Tuna
authors.forename: B
authors.initials: B
authors.lastname: Caglayan
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D009543:Nifedipine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002110:Caffeine; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009543:Nifedipine