Chronic relapsing inflammatory polyneuropathy complicating sicca syndrome.

although the latter is more potent and has a isolated caudate slices by one minute longer plasma half-life.3 exposure to 20mM K' induced a tritium Given their mild D2 blocking effect in overflow of 3-9% of tissue content. Cinnaaddition to their calcium entry channe. rizine, flunarizine and nifedipine at doses antagonist activity, it has been speculated able to block calcium channels lowered the that either or both of these properties could total tritium overflow elicited by potassium. account for their unwanted etrapyramidal Since dopamine release by potassium effects. To date we have studied over 100 stimulation depends on a calcium mechpatients showing that these complications anism, our findings suggest that Parkinare not uncommon and may lead to personism induced by these drugs is caused by manent disabilities as in patients with tartheir calcium antagonism. dive dyskinesias. Further research is needed to evaluate any To provide a deeper insight into their possible effect on dopamine presynaptic mechanisms of action we studied the effects receptors. of cinnarizine, flunarizine and nifedipine on Clinical and experimental evidence indithe release of 3H dopamine from the rat cates that patients on calcium antagonist caudate nucleus. drugs should be closely monitored to disMale Wistar rats (150-200 g body weight) close early extrapyramidal side-effects. were decapitated and 1 0mm coronal brain MANUEL FERNANDEZ PARDAL* slices prepared. Slices corresponding to JULIO FERNANDEZ PARDALt 1-5-2-5mm rostrally to the anterior commisFEDERICO MICHELI* sure were selected and a prism of caudate *Hospital de Clinicas Jose de San Martin, nucleus removed. Krebs solution4 equiliDepartment of Neurology, brated with 95% 02 at 37C was employed. University of Buenos Aires, Endogenous stores of dopamine were Cordoba 2351, Buenos Aires. labelled in vitro by incubating the tissue for tCEFAPRIM, 30 min with lOCi, of (2,5,6,3H) dopamine. CONICET Buenos Aires Following incubation, tissue samples were Argentina. transferred to an open cylinder with a piece of nylon mesh of 100 filaments per cm2 Address correspondence to: Dr F Micheli. placed at the bottom and forming a small basket. The whole device was placed in tube containing 3ml of Krebs solution. Tissue References slices were then exposed to eight 1 min, then to ten 5 min and again to ten 1 min washing I Marti Mass6 JF, Obeso JA, Carrera N, Marperiods. The tissue was stimulated by I min tinez Lage JM. Aggravation of Parkinson's exposure to medium containing 20mM K +. disease by cinnarizine. J Neurol Neurosurg Stimulation was immediately followed by Psychiatry 1987;50:804-5. several 1 minute washings until the basal 2 Micheli F, Fernandez Pardal MM. Gatto E, level of tritium overflow had been reached. et al. Flunarizine and Cinnarizine-induced