“In rats, pretreated with naloxone, there was restoration as well as augmentation of morphine- induced antinociception in the presence of L- glutamic acid with an increase in TFL (9.0 ± 0.4 sec; P < 0.0001).”
“Intrathecal administration of L- glutamic acid attenuated the antinociceptive effect of intrathecal morphine with a decrease in TFL (1.4 ± 0.3 sec; P < 0.0001) from 6.6 ± 0.3 sec. Ketamine led to abolition of this effect (P < 0.01).”