Calcium channel agonist, (+/-)-Bay K8644, causes a transient increase in striatal monoamine oxidase activity in Balb/c mice.
We investigated in vivo effects of the L-type calcium channel agonist 1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl) phenyl] pyridine-3-carboxylic acid ((+/-)-Bay K8644) on mitochondrial monoamine oxidase (MAO) activity and striatal dopamine (DA) content employing fluorimetric and HPLC-electrochemical procedures, respectively. (+/-)-Bay K8644 administration resulted in visible behavioral dysfunctions in mice. A reversible dose-independent inhibition of striatal DA levels and a significant increase in the brain mitochondrial MAO-A and -B activities were observed in animals treated with the calcium agonist. A positive relationship between the rise in the enzyme activity and decrease in DA content in (+/-)-Bay K8644 treated animals indicates a direct, but transient effect of this channel activator on DA metabolism, which may be related to acute behavioral syndromes exhibited following administration of the drug. Moreover, a direct involvement of L-type dihydropyridine sensitive calcium channels is indicated in this action, since nicardipine could effectively attenuate (+/-)-Bay K8644-induced behavioral aberrations, or block the striatal DA depletion and the increase in MAO activity. The present results have far-reaching implications in neuropharmacological research, where co-treatment of calcium channel drugs and MAO inhibitors are warranted.
Division of Neurosciences, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, 700 032, Calcutta, India.
Supriti
S
Samantaray
Goutam
G
Chandra
Kochupurackal P
KP
Mohanakumar
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000818:Animals; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000187:drug effects* / Q000201:enzymology*; D004298:Dopamine / Q000378:metabolism; D005470:Fluorometry; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000201:enzymology; D008995:Monoamine Oxidase / Q000187:drug effects* / Q000378:metabolism*
D002120:Calcium Channel Agonists; D020746:Calcium Channels, L-Type; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D008995:Monoamine Oxidase; D004298:Dopamine