The intracerebroventricular injection of pyridoxal phosphate (PLP, 0.125-1.25 mumol/rat) causes epileptic seizures (4 min leads to 1 min) that are preventable or reversible by GABA (1 mumol/rat), by muscimol (0.025 mumol/rat), or by diazepam (1.75 mumol/rat). At the peak of PLP-induced convulsions, the activities of GAD and GABA-T in 14 regions of rat brain… (More)
The effect of serotonin on glutamate decarboxylase and GABA-transaminase was studied, in vitro, in synaptosome homogenates from rat mesencephalon. Serotonin dissolved in the incubation medium inhibits glutamate decarboxylase activity and stimulates GABA-transaminase activity.
L-glutamate and kainate administered intracerebroventricularly (i.c.v.) both produced dose-dependent increases in rat cerebellar cGMP. The increased cGMP produced by L-glutamate, but not that produced by kainate, could be completely abolished by the glutamate antagonist glutamate diethylester which had no effect alone. The data suggest that L-glutamate and… (More)
Cerebellar cyclic GMP levels can be altered by neurotransmitters and their receptor agonists and antagonists. In this study, we investigated the action of noradrenaline and certain drugs affecting alpha- and beta-adrenoceptors on rat cerebellaceptor agonists such as methoxamine and phenylephrine increased cGMP levels. alpha-Adrenoceptor antagonists such as… (More)