抄録
1. The effect of serotonin on the evoked responses in the cerebral cortex of mintal anaesthetized cat, was examined through an electrophysiological method.
2. Serotonin was topically applied on the cortical surface in the first part of the experiments, whereas the said agent was given by intravascular injection in the second part. The concentration of the applied agent ranged from 1 to 1000γ per cc.
3. In the variety of the evoked potentials such as somato-sensory response, , direct cortical response and callosal response, topically administered serotonin (particularly in 10γ per cc solution) resulted the depression of negative phases unanimously.
4. No significant potential change was observed in somato-sensory response following infusion of 1-1000γ serotonin and 5 HTP (with or without pretreatment. with iproniazid).
5. Long-lasting type of potential change with no particulr change within, the first 30 min., showed gradual increase of evoked activity over 2 hrs., after intra-carotid injection of 100γ -serotonin.
6. These prolonged facilitations were modified more by the pretreatment with reserpine than with chlorpromazine.
7. Topical application of 10γ -LSD produced the reduction of surface negative component in somato-sensory response.
8. From the above observations, the author would like to draw the con-clusion that;
a) the effect of directly applied serotonin is the result of the inhibition of post-synaptic transmission of cortical neurons.
b) the prolonged facilitation following intra-arterial infusion of serotonin is presumably attributable to the secondary effects of serotonin.
c) serotonin and 5 HTP, precursor of serotonin, cannot pass through the blood-brain-barrier under these conditions.
d) no antagonistic action between serotonin and LSD was observed as far as this set of experiments is concerned.
