[Possible relation between learning and non-template RNA synthesis in neurons].

A substrate of either matrix-(cytidinetriphosphate, CTPh) or non-matrix (cytidinediphosphate, CDPh, or uridinediphosphate, UDPh) RNA synthesis was injected into mollusc neurone by means of intracellular microionophoresis. Subsequently, habituation was elaborated, assuming that if this process depends on the RNA synthesis, then the formation of defective RNA molecules with an excessive content of cytidine or uridine will disturb the learning process. In control experiments, habituation was elaborated either without drugs administration or following an injection of cytidinemonophosphate non subject to polymerization, or of an equimolar mixture of four ribonucleotidediphosphates: CDPh+UDPh+ADPh++GDPh. In the latter case a minimal distortion of the ratio between the initial substrates of the non-matrix RNA synthesis was expected. Both in the control experiments and following CTPh administration, the habituation was attended with an increase of threshold and latencies of spikes evoked by repeated stimuli. Injection of CDPh or UDPh disturbed the dynamics of thresholds and latencies increase in the course of habituation. The data obtained suggest that the habituation process is connected with a non-matrix synthesis of RNA in the neurones.