[The effects of elevated calcium concentrations in artificial cerebrospinal fluid on pial arteries during perivascular microperfusion and the Ca++-antagonistic effect of bencyclane (author's transl)].

The influence of artificial cerebrospinal fluid (CSF) containing 6, 9 and 18 mEq/l Ca++, respectively, on 145 pial arteries of nine anesthetized cats was investigated by the perivascular microperfusion technique. The higher the concentration of Ca++ in the perivascular space and the longer these high Ca++ concentrations acted on the vascular wall, the more pronounced were the constrictions of the arteries. If N-[3-(1-benzyl-cycloheptyloxy)-propyl]-N,N-dimethyl-amine (bencyclane-hydrogenfumarate, Fludilat) (10 mg/100 ml) was added to the CSF, dilatations occurred, even if the concentrations of Ca++ were higher than in normal CSF (3 meq/l). The degree of dilatation, however, was dependent on the Ca++ concentration in the CSF. With high Ca++ in the CSF the dilatatory action of bencyclane was inhibited when K+ and H+ in the CSF were kept constant. The reaction can be described as Ca++ antagonism, the possible mechanisms of which are discussed.