MODULATION OF POTASSIUM EVOKED SECRETORY FUNCTION IN RAT CEREBELLAR SLICES MEASURED BY REAL-TIME MONITORING - EVIDENCE OF A POSSIBLE ROLE FOR METHYLFOLATE IN CEREBRAL TISSUE

The real time dynamics of K+ evoked neurosecretion in cerebellar slices has been monitored electrochemically. In the presence of 5-methyltetrahydrofolate a statistically significant diminution in secretory response occurs. Agonists to probe the pharmacological basis for this indicate it is not due to voltage sensitive Ca2+. channel blockade, nor does it show any similarity of effect with kainate, whose receptor is a putative binding site for 5-methyltetrahydrofolate. The method is fully validated, although no account is taken of individual molecular species. High performance liquid chromatography combined with off line microbiological assay could only detect 5-methyltetrahydrofolate in cerebrospinal fluid. We therefore discuss our findings in relation to possible cerebral roles for cerebrospinal fluid 5-methyltetrahydrofolate in the context of both membrane and transmitter related interactions.