COMPARISON AMONG THE EFFECTS OF NIFEDIPINE, NIMODIPINE AND NISOLDIPINE ON THE BRAIN BIOGENIC-AMINES OF NORMAL OR HALOPERIDOL TREATED RATS

1. Previous studies have shown that dihydropyridine calcium antagonist s affected the metabolism of the brain biogenic amines more extensivel y than the non-dihydropyridine ones. The effects of three dihydropyrid ines (nifedipine, nimodipine or nisoldipine, 0.05-0.10 mmol/kg i.p.) o n brain monoamines and metabolites have been evaluated on both normal and haloperidol treated rats. 2. The small changes induced by the drug s on normal rats were markedly increased in the haloperidol treated ra ts, clearly showing an inhibition of dopaminergic systems. 3. These ef fects were selective for the striatum and cerebral cortex, with nisold ipine being more effective than nimodipine or nifedipine. 4. The effec ts of the three drugs on serotonergic systems were similar or more mar ked on haloperidol treated rats than on normal rats. These effects, sh owing activation of serotonergic systems, displayed some regional spec ificity and different potency of the three compounds. Nisoldipine also appeared to be the most effective drug on serotonergic systems. 5. In conclusion nisoldipine, as well as other calcium antagonists, may hav e a place in the treatment of some mood disorders.