title: Different effects of the calcium antagonists nimodipine and flunarizine on dopamine metabolism in the rat brain.
abstract: The effect of two calcium antagonists, nimodipine and flunarizine, on striatal dopamine (DA) metabolism in rats was compared. Flunarizine (5-20 mg/kg i.p.) caused a dose-dependent increase in the DA metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC) in the caudate nucleus. Following the 20 mg/kg dose, DOPAC levels were maximally elevated by about 50% from 2 to 12 hrs after treatment. On the contrary, nimodipine at the dose of 20 mg/kg i.p. produced a modest decrease in DOPAC levels. Neither calcium antagonist modified DA content. However, both nimodipine and flunarizine, at the dose of 20 mg/kg, markedly reduced the accumulation of DOPAC in the caudate nucleus induced by haloperidol (1 mg/kg). It is suggested that flunarizine, but not nimodipine, has a neuroleptic-like action, whereas the two calcium antagonists have in common the ability to attenuate the hyperactivity of DA neurons.
authors.affiliation: Institute of Physiology, University of Cagliari, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Fadda
authors.forename: G L
authors.initials: GL
authors.lastname: Gessa
authors.forename: E
authors.initials: E
authors.lastname: Mosca
authors.forename: E
authors.initials: E
authors.lastname: Stefanini
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005444:Flunarizine / Q000494:pharmacology*; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D009553:Nimodipine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002121:Calcium Channel Blockers; D015102:3,4-Dihydroxyphenylacetic Acid; D009553:Nimodipine; D006220:Haloperidol; D005444:Flunarizine; D004298:Dopamine