the influence of serotonergic system on the changes in locomotor activity of mice and rats brought about by morphine , fentanyl , codeine and pentazocine and on morphine induced catalepsy in rats was studied . p-chlorophenylalanine ( pcpa ) did not affect the behavioral changes produced in mice by morphine , fentanyl , codeine and pentazocine but reduced the behavioral depression produced by these drugs in rats .
C0026549
morphine
C0009214
codeine