Action mechanism of 2-amino-4-phenylthiazole, a piscine anesthetic, upon the central nervous system of carp.

Abstract

The physio-chemical characteristics of a sedative, 2-amino-4-phenylthiazole, as to its anesthetic properties upon carp (Cyprinus carpio) were surveyed. (1) EEG activation by acetylcholine chloride administered into the cerebellum was observed under concomitant debilitation of EEG from the cerebellum by anesthetization. EEG activation was also observed by serotonin-creatinine sulfate or dopamine hydrochloride, but not by noradrenaline hydrochloride. (2) This compound gave neither extreme activitation nor inhibition upon the monoamine oxidase (EC 1.4.3.4) or acetylcholine hydrolase (EC 3.1.1.7) activity. (3) The depletion of acetylcholine in the nerve ending particles was observed under anesthetization. The depletion of serotonin or dopamine was not observed. It might be concluded that the depletion of acetylcholine resulted in the inhibition of choline o-acetyltransferase (EC 2.3.1.6) activity and the abatement of acetylcholine binding capacity of the synaptic vesicles in the presence of this compound. (4) The brain cAMP was observed to be increased by the anesthetization. Although the implications as for the augmentation of brain cAMP was not yet fully elucidated, it was concluded that the augmentation resulted from inhibition of cAMP phosphodiesterase (EC 3.1.4.1) activity in the presence of this compound.