Antagonism of phencyclidine-induced hyperactivity by glycine in mice.

We tested the effect of glycine on phencyclidine (PCP)-induced hyperactivity in mice. Glycine antagonized the locomotor stimulating effect of PCP. Correlation was found between the degree of antagonistic effect and the size of the increase in glycine in the brain. The antagonism is not due to changes in uptake, since the elevation of glycine in plasma and brain had no effect on the cerebral uptake of PCP. This pharmacological action of glycine appears to be a central effect, but some peripheral effect can not be excluded. Since glycine is not toxic at levels needed for PCP antagonism, it could be considered for ameliorating PCP psychosis. The locomotor stimulating effect of PCP is strain dependent in mouse. Some strains are responsive, such as BALB/cBy and CXBK, and some are unresponsive, such as C57BL/6 and CXBH.