The relative significance of spinal cord norepinephrine and 5-hydroxytryptamine in electrically-induced seizure in the rat

The effects of various drug treatments on spinal cord norepinephrine (NE) and 5-hydroxy-tryptamine (5-HT) were compared to the effects of these same treatments on electrically-induced spinal cord seizure. Depletion of NE stores by 6-hydroxydopamine (6-OH-DA) facilitates spinal cord seizures. Desipramine-induced protection of noradrenergic neurones against the depleting effect of 6-OH-DA affords complete protection against seizure facilitation and unmasks an anticonvulsant effect of 6-OH-DA. Depletion of spinal cord 5-HT stores by p-chlorophenylalanine (PCPA) and 5,7-dihydroxy-tryptamine (5,7-DHT) does not enhance spinal cord seizures. Thus, it appears that spinal cord norad-renergic but not 5-hydroxytryptaminergic neurones act as attenuators of seizure activity.