[Blood circulation, oxygen pressure and pH of the cerebral cortex under the influence of bencyclane].

The effect of N-[3-(1-benzyl-cycloheptyl-oxy)-propyl]-N,N-dimethyl-amine (bencyclan-hydrogenfumarate, Fludilat¿ on the cerebral vascular system was studied by means of the following methods: 1. In pigs regional cerebral cortical blood flow was continuously recorded with a heat conduction device, cortical pH with a glass electode in which the flat measuring surface and the reference were close together. Cortical pO2 was recorded with a multiwire platinum electrode. Systemic arterial blood pressure was monitored by means of a Statham transducer. 2. In a second series in cats the perivascular space of small pial arteries or arterioles was perfused with cerebro-spinal fluid (CSF) to which bencyclan had been added. The perfusion was performed by means of micropipettes. Local cortical blood flow increased slightly for some minutes after slow infusion of 1--3 mg/kg bencyclan. Rapid injection caused initially a significant decrease in arterial blood pressure, which was accompanied by a transient decrease in CBF and in cortical pH. After the return of the arterial blood pressure to its initial value, CBF increased. Cortical pO2 and cortical pH returned to initial values. After slow infusion of the substance the pH variation was usually very slight or it was missed completely. Perivascular microperfusion wtih CSF containing bencyclan caused dilatation of those pial sections which were in contact with the drug. High concentration of the drug caused stronger dilatations than did low concentrations. It is concluded that the substance causes dilatations of the cerebral vessels and that this dilatation occurs also during constant perivascular pH.